mgmt-cluster dressup for maestro consumer

[geoberle]

What this PR does

this MR introduces the ability to dress up an MC to run a maestro consumer that can connect to the regional maestro infrastructure.

this includes

• the setup of eventgrid access with fine grained topic permissions for the MC
• the setup of a client certificate in key vault for the MC
• managed identity and CSI secret store setup to access the certificate on the MC
• developer documentation

additionally some refactoring on the existing maestro bicep modules was conducted, to support hosting eventgrid and key vault infra in resource groups different from clusters interacting with them.

Jira:

Special notes for your reviewer

Checklist

This checklist is not enforcing, but it's a reminder of items that could be relevant to every PR.
Approvers are expected to review this list.

• PR: The PR description is expressive enough and will help future contributors
• Code: Write code that humans can understand and Keep it simple
• Refactor: You have left the code cleaner than you found it (Boy Scout Rule)
• Upgrade: Impact of this change on upgrade flows was considered and addressed if required
• Deployment: The deployment process was considered and addressed if required
• Testing: New code requires new unit tests.
• Documentation: Is the documentation updated? Either in the doc located in focus area, in the README or in the code itself.
• Customers: Is this change affecting customers? Is the release plan considered?