Add Package Registry preview extension

[Kai Daniels (kaidaniels13)]

Related command

az alrs

Adds the initial preview extension with AAZ-generated registry management commands and custom repository, release, package, distribution, remote, publication, and task commands. The ARM contract is under review in Azure/azure-rest-api-specs#46218. Product naming, the data-plane audience and endpoint contract, AAZ publication, recorded ScenarioTests, and PPE validation remain draft blockers.

General Guidelines

• Ran azdev style alrs locally.
• Ran python scripts/ci/test_index.py -q locally.
• Extension version follows the preview version schema.

For new extensions:

• Extension description follows the summary guidelines.

Review questions

• Is the command grouping and generated/custom split appropriate for the initial preview?
• What should change before the extension is ready for recorded testing and publication?

[azure-client-tools-bot-prd]

Hi Kai Daniels (@kaidaniels13),
Please write the description of changes which can be perceived by customers into HISTORY.rst.
If you want to release a new extension version, please update the version in pyproject.toml (or setup.py, if the extension has not migrated yet) as well.

[azure-pipelines]

Azure Pipelines:
There may be pipelines that require an authorized user to comment /azp run to run.

[microsoft-github-policy-service]

Thank you for your contribution Kai Daniels (@kaidaniels13)! We will review the pull request and get back to you soon.

[Yong Zhang (yonzhan)]

alrs