feat(cwl): initialize tailLogGroup command. starts stream and prints logEvents to textDocument

[keeganirby]

Problem

TailLogGroup currently is just logging the Users WizardResponse. It does not start a LiveTail stream or print results to the VSCode editor

Solution

• Creates a LiveTailSession with the input params from the TailLogGroupWizard
• Registers the LiveTailSession in the LiveTailSessionRegistry
• Iterates the Response Stream and prints new LogEvents to a TextDocument
• If there are no open tabs for a given session's TextDocument, the stream will be closed by triggering its AbortController and disposing its client.

We will use a new URI Scheme for LiveTail text documents so we can identify a LiveTail session vs a Cloudwatch SearchLogGroup/ViewLogStream document. In the future, we will register LiveTail specific CodeLenses that depend upon this URI scheme. Defining a new URI scheme for a Text Document requires a Document Provider. In this use case, it is empty given that the response handling that writes to the document lives within the TailLogGroup command itself.

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License: I confirm that my contribution is made under the terms of the Apache 2.0 license.

[github-actions]

This pull request modifies code in src/ but no tests were added/updated. Confirm whether tests should be added or ensure the PR description explains why tests are not required.

[github-actions]

This pull request implements a feature or fix, so it must include a changelog entry. See CONTRIBUTING.md#changelog for instructions.

[keeganirby]

Spoke with Josh about this during the initial PR: will add a Changelog when the feature branch is complete and ready to merge to master.