feat(Docker): add "Start Local Kafka" command/action

[shouples]

Summary of Changes

As a follow-up to #347, this PR adds the functionality for creating a confluent-local Kafka broker container through the Docker engine API.

TODO:

• update docker event listener to check container listing before setting localKafkaConnected.fire(false)
• handle progress notification cancellation behavior
• handle errors creating/starting container

Any additional details or context that should be provided?

Beyond the command added in https://github.com/confluentinc/vscode/blob/djs/local-kafka-start/src/commands/docker.ts, this PR is also adding some wrappers around the basic movements we'll need going forward to check for the existence of Docker images (and pull if they don't exist), create Docker networks, create and start Docker containers.

This PR also adds a LocalResourceWorkflow abstract base class for creating "workflows" to start and stop local resources depending on the base image chosen by the user in our extension settings. Initially, this is just for the confluentinc/confluent-local Docker image, but will be extended in future PRs for supporting additional images.

Associated PRs

• feat(Docker): add "Start Local Kafka" command/action  #396 👈
  • feat(Docker): add "Shutdown Local Kafka" command/action #399
    • add LocalSchemaRegistry class and update general SR handling for local instances #400
      • feat(Docker): add "Start Local Kafka with Schema Registry" command/action #401
        • placeholder for "Shutdown Local Kafka with Schema Registry" branch
          • placeholder for local connection management cleanup branch

Pull request checklist

Please check if your PR fulfills the following (if applicable):

Tests

• Added new
• Updated existing
• Deleted existing

Other

• Does anything in this PR need to be mentioned in the user-facing CHANGELOG or README?
• Have you validated this change locally by packaging and installing the extension .vsix file?

  gulp clicktest