[ACR] [Pending service update] [Pre-GA] Finalize cloud configuration API

[annelo-msft]

The service will be making changes to how users can authenticate with it. Given this, we'll want to revisit and potentially replace the AuthorizationScope property on ContainerRegistryClientOptions with an API that

(in order of preference)

• (if General ACR scope enables this) makes it unnecessary for customer to specify cloud
• Arch board guidance specifies how users can indicate which cloud in a Track 2 consistent way
• If the service provides two permissions models with different scopes associated with them, we would provide an API that communicates the differences between the two models, and either guides the user to choose the appropriate scope, or specifies it for them.

[See updated API description below]

[annelo-msft]

Per conversations with @schaabs and @AlexGhiondea, we will make the following changes to the API:

• Provide an Audience property in ClientOptions, replacing the AuthorizationScope property from the Beta 3 API
• Audience is an extensible enum, listing the known clouds, but user can override with a string if needed
• If Audience is set, client library will append /.default to Audience to specify the default scope
• Audience will default to data-plane scope root, which should be common across clouds

[annelo-msft]

Moving to August per internal discussion.

[annelo-msft]

Proposed APIView here: https://apiview.dev/Assemblies/Review/ba57bf904e524ce3bf647dad124ddc7c/b7bc17cdde3d4cce9d746014f58e91d7?diffRevisionId=d901b2eecfc1401ca50a1118fcf7d8b8&doc=False&diffOnly=False

With samples