Refactor AzurePublisher to enable usage in downstream publishers

[sunandabalu]

Description

Few refactoring changes to AzurePublisher to enable usage in downstream publishers:

• Refactor the logic in AzurePublisher to a new public AzurePublishingContext class.
• refactor code in AzurePublisher.PublishAsync to AzurePublishingContext and capture bicep compilation data that is thrown away in the existing AzurePublisher.PublishAsync method

Fixes # (issue)

Checklist

• Is this feature complete?
  • Yes. Ready to ship. (although it is under Experimental attribute)
• Are you including unit tests for the changes and scenario tests if relevant?
  • Yes
• Did you add public API?
  • Yes
    • If yes, did you have an API Review for it?
      • No
    • Did you add <remarks /> and <code /> elements on your triple slash comments?
      • Yes
• Does the change make any security assumptions or guarantees?
  • No
• Does the change require an update in our Aspire docs?
  • No

[davidfowl]

this PR doesn't need a playground sample.

[eerhardt]

Thanks, @sunandabalu, for the great start on this PR! I tweaked it a little bit and added a test for the new functionality. I believe this PR is ready for review.

Note I took an approach with the public API for now. We can tweak the public API as we go and learn more. It is currently marked as [Experimental], so we can update it in the future.