[Feature] Add databricks_budget resource (#3955)

## Changes
Add support for account-level
[Budget](https://docs.databricks.com/api/account/budgets) resource

Example structure
```
resource "databricks_budget" "this" {
    display_name = "data-science-budget"

    alert_configurations {
        time_period         = "MONTH"
        trigger_type        = "CUMULATIVE_SPENDING_EXCEEDED" 
        quantity_type       = "LIST_PRICE_DOLLARS_USD"
        quantity_threshold  = "840"

        action_configurations {
            action_type = "EMAIL_NOTIFICATION"
            target      = "me@databricks.com"
        }
    }

    filter {
        workspace_id {
            operator = "IN"
            values   = [
                1234567890098765
            ]                              
        }
        tags {
            key   = "Databricks"
            value {
                operator = "IN"
                values = ["Data Science"]
            }
        }
    }
}
```

Resolves #3887

## Tests
- [x] `make test` run locally
- [x] relevant change in `docs/` folder
- [x] covered with integration tests in `internal/acceptance`
- [ ] relevant acceptance tests are passing
- [x] using Go SDK

---------

Co-authored-by: Alex Ott <alexott@gmail.com>

docs/resources/budget.md

@@ -0,0 +1,103 @@
+---
+subcategory: "FinOps"
+---
+# databricks_budget Resource
+
+-> **Note** Initialize provider with `alias = "account"`, and `host` pointing to the account URL, like, `host = "https://accounts.cloud.databricks.com"`. Use `provider = databricks.account` for all account-level resources.
+
+-> **Public Preview** This feature is in [Public Preview](https://docs.databricks.com/release-notes/release-types.html).
+
+This resource allows you to manage [Databricks Budgets](https://docs.databricks.com/en/admin/account-settings/budgets.html).
+
+## Example Usage
+
+```hcl
+resource "databricks_budget" "this" {
+  display_name = "databricks-workspace-budget"
+
+  alert_configurations {
+    time_period         = "MONTH"
+    trigger_type        = "CUMULATIVE_SPENDING_EXCEEDED"
+    quantity_type       = "LIST_PRICE_DOLLARS_USD"
+    quantity_threshold  = "840"
+
+    action_configurations {
+      action_type = "EMAIL_NOTIFICATION"
+      target      = "abc@gmail.com"
+    }
+  }
+
+  filter {
+    workspace_id {
+      operator = "IN"
+      values   = [
+        1234567890098765
+      ]
+    }
+    
+    tags {
+      key   = "Team"
+      value {
+        operator = "IN"
+        values = ["Data Science"]
+      }
+    }
+
+    tags {
+      key   = "Environment"
+      value {
+        operator = "IN"
+        values = ["Development"]
+      }
+    }
+  }
+}
+```
+
+## Argument Reference
+
+The following arguments are available:
+
+* `display_name` - (Required) Name of the budget in Databricks Account.
+
+### alert_configurations Configuration Block (Required)
+
+* `time_period` - (Required, String Enum) The time window of usage data for the budget. (Enum: `MONTH`)
+* `trigger_type` - (Required, String Enum) The evaluation method to determine when this budget alert is in a triggered state. (Enum: `CUMULATIVE_SPENDING_EXCEEDED`)
+* `quantity_type` - (Required, String Enum) The way to calculate cost for this budget alert. This is what quantity_threshold is measured in. (Enum: `LIST_PRICE_DOLLARS_USD`)
+* `quantity_threshold` - (Required, String) The threshold for the budget alert to determine if it is in a triggered state. The number is evaluated based on `quantity_type`.
+* `action_configurations` - (Required) List of action configurations to take when the budget alert is triggered. Consists of the following fields:
+  * `action_type` - (Required, String Enum) The type of action to take when the budget alert is triggered. (Enum: `EMAIL_NOTIFICATION`)
+  * `target` - (Required, String) The target of the action. For `EMAIL_NOTIFICATION`, this is the email address to send the notification to.
+
+### filter Configuration Block (Optional)
+
+* `workspace_id` - (Optional) Filter by workspace ID (if empty, include usage all usage for this account). Consists of the following fields:
+  * `operator` - (Required, String Enum) The operator to use for the filter. (Enum: `IN`)
+  * `values` - (Required, List of numbers) The values to filter by.
+* `tags` - (Optional) List of tags to filter by. Consists of the following fields:
+  * `key` - (Required, String) The key of the tag.
+  * `value` - (Required) Consists of the following fields:
+    * `operator` - (Required, String Enum) The operator to use for the filter. (Enum: `IN`)
+    * `values` - (Required, List of strings) The values to filter by.
+
+## Attribute Reference
+
+In addition to all arguments above, the following attributes are exported:
+
+* `budget_configuration_id` - The ID of the budget configuration.
+* `account_id` - The ID of the Databricks Account.
+
+## Import
+
+This resource can be imported by Databricks account ID and Budget.
+
+```sh
+terraform import databricks_budget.this '<account_id>|<budget_configuration_id>'
+```
+
+## Related Resources
+
+The following resources are used in the context:
+
+* [databricks_mws_workspaces](mws_workspaces.md) to set up Databricks workspaces.

finops/resource_budget.go

@@ -0,0 +1,102 @@
+package finops
+
+import (
+	"context"
+	"strings"
+
+	"github.com/databricks/databricks-sdk-go/service/billing"
+	"github.com/databricks/terraform-provider-databricks/common"
+	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
+	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/validation"
+)
+
+func ResourceBudget() common.Resource {
+	s := common.StructToSchema(billing.BudgetConfiguration{}, func(m map[string]*schema.Schema) map[string]*schema.Schema {
+		common.CustomizeSchemaPath(m, "display_name").SetValidateFunc(validation.StringLenBetween(1, 128))
+		for _, p := range []string{"account_id", "budget_configuration_id", "create_time", "update_time"} {
+			common.CustomizeSchemaPath(m, p).SetComputed()
+		}
+		common.CustomizeSchemaPath(m, "alert_configurations", "alert_configuration_id").SetComputed()
+		common.CustomizeSchemaPath(m, "alert_configurations", "action_configurations", "action_configuration_id").SetComputed()
+		// We need SuppressDiff because API returns a string representation of BigDecimal with a lot
+		// of trailing 0s, etc.
+		common.CustomizeSchemaPath(m, "alert_configurations", "quantity_threshold").SetCustomSuppressDiff(func(k, old, new string, d *schema.ResourceData) bool {
+			normalize := func(v string) string {
+				if strings.Contains(v, ".") {
+					v = strings.TrimRight(v, "0")
+					v = strings.TrimSuffix(v, ".")
+				}
+				return v
+			}
+			return normalize(old) == normalize(new)
+		})
+		return m
+	})
+	p := common.NewPairID("account_id", "budget_configuration_id")
+	return common.Resource{
+		Create: func(ctx context.Context, d *schema.ResourceData, c *common.DatabricksClient) error {
+			var create billing.CreateBudgetConfigurationBudget
+			common.DataToStructPointer(d, s, &create)
+			acc, err := c.AccountClient()
+			if err != nil {
+				return err
+			}
+			budget, err := acc.Budgets.Create(ctx, billing.CreateBudgetConfigurationRequest{Budget: create})
+			if err != nil {
+				return err
+			}
+			d.Set("budget_configuration_id", budget.Budget.BudgetConfigurationId)
+			d.Set("account_id", c.Config.AccountID)
+			common.StructToData(budget.Budget, s, d)
+			p.Pack(d)
+			return nil
+		},
+		Read: func(ctx context.Context, d *schema.ResourceData, c *common.DatabricksClient) error {
+			_, id, err := p.Unpack(d)
+			if err != nil {
+				return err
+			}
+			acc, err := c.AccountClient()
+			if err != nil {
+				return err
+			}
+			budget, err := acc.Budgets.GetByBudgetId(ctx, id)
+			if err != nil {
+				return err
+			}
+			return common.StructToData(budget.Budget, s, d)
+		},
+		Update: func(ctx context.Context, d *schema.ResourceData, c *common.DatabricksClient) error {
+			var update billing.UpdateBudgetConfigurationBudget
+			_, id, err := p.Unpack(d)
+			if err != nil {
+				return err
+			}
+			common.DataToStructPointer(d, s, &update)
+			acc, err := c.AccountClient()
+			if err != nil {
+				return err
+			}
+			budget, err := acc.Budgets.Update(ctx, billing.UpdateBudgetConfigurationRequest{
+				Budget:   update,
+				BudgetId: id,
+			})
+			if err != nil {
+				return err
+			}
+			return common.StructToData(budget.Budget, s, d)
+		},
+		Delete: func(ctx context.Context, d *schema.ResourceData, c *common.DatabricksClient) error {
+			_, id, err := p.Unpack(d)
+			if err != nil {
+				return err
+			}
+			acc, err := c.AccountClient()
+			if err != nil {
+				return err
+			}
+			return acc.Budgets.DeleteByBudgetId(ctx, id)
+		},
+		Schema: s,
+	}
+}