Add Redis member store for ACA provider and manage stale members

[sfmskywalker]

Description

This PR adds a Redis store implementation as an alternative option to using Azure Resource tagging.

In addition, the ACA cluster provider is updated to remove stale member entries. This monitoring logic, as wel las registering and unregistering members, has been moved to an actor class to keep the provider class itself clean.

Purpose

This pull request is a:

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)