chore: document sdk (#919)

## Description

Adds documentation around importing the `sdk` package from Pepr.

## Related Issue

Fixes #914
<!-- or -->
Relates to #

## Type of change

- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [x] Other (security config, docs update, etc)

## Checklist before merging

- [x] Test, docs, adr added or updated as needed
- [x] [Contributor Guide
Steps](https://docs.pepr.dev/main/contribute/#submitting-a-pull-request)
followed

---------

Signed-off-by: Case Wylie <cmwylie19@defenseunicorns.com>

docs/030_user-guide/015_sdk.md

@@ -1,5 +1,11 @@
 # Pepr SDK
 
+To use, import the `sdk` from the `pepr` package:
+
+```typescript
+import { sdk } from "pepr";
+```
+
 ## `containers`
 
 Returns list of all containers in a pod. Accepts the following parameters:
@@ -12,24 +18,28 @@ Returns list of all containers in a pod. Accepts the following parameters:
 **_Get all containers_**
 
 ```typescript
+const { containers } = sdk;
 let result = containers(peprValidationRequest)
 ```
 
 **_Get only the standard containers_**
 
 ```typescript
+const { containers } = sdk;
 let result = containers(peprValidationRequest, "containers")
 ```
 
 **_Get only the init containers_**
 
 ```typescript
+const { containers } = sdk;
 let result = containers(peprValidationRequest, "initContainers")
 ```
 
 **_Get only the ephemeral containers_**
 
 ```typescript
+const { containers } = sdk;
 let result = containers(peprValidationRequest, "ephemeralContainers")
 ```
 
@@ -44,6 +54,7 @@ Returns the owner reference for a Kubernetes resource. Accepts the following par
 **Usage:**
 
 ```typescript
+const { getOwnerRefFrom } = sdk;
 const ownerRef = getOwnerRefFrom(kubernetesResource);
 ```
 
@@ -63,6 +74,7 @@ Write a K8s event for a CRD. Accepts the following parameters:
 **Usage:**
 
 ```typescript
+const { writeEvent } = sdk;
 writeEvent(
   kubernetesResource,
   event,
@@ -84,6 +96,7 @@ Returns a sanitized resource name to make the given name a valid Kubernetes reso
 **Usage:**
 
 ```typescript
+const { sanitizeResourceName } = sdk;
 const sanitizedResourceName = sanitizeResourceName(resourceName)
 ```