[DO NOT MERGE] [SQL] Add Managed Instance DNS alias cmdlets

[krivi37]

Description

Added commands for managing Managed Instance DNS aliases: New, Get, Set, Move, Remove. Please do not merge yet, we need only a review.

Checklist

• [X] I have read the Submitting Changes section of CONTRIBUTING.md
• [X] The title of the PR is clear and informative
• [X] The appropriate ChangeLog.md file(s) has been updated:
  • For any service, the ChangeLog.md file can be found at src/{{SERVICE}}/{{SERVICE}}/ChangeLog.md
  • A snippet outlining the change(s) made in the PR should be written under the ## Upcoming Release header -- no new version header should be added
• [X] The PR does not introduce breaking changes
• [X] If applicable, the changes made in the PR have proper test coverage
• [x] For public API changes to cmdlets:
  • [X] a cmdlet design review was approved for the changes in this repository (Microsoft internal only)
    • https://github.com/Azure/azure-powershell-cmdlet-review-pr/issues/1215
  • [X] the markdown help files have been regenerated using the commands listed here

[isra-fel]

@krivi37 Hello, the pull request looks good to us. However I noticed you've added the "Do not merge" label. What's your plan on this PR?

[krivi37]

@krivi37 Hello, the pull request looks good to us. However I noticed you've added the "Do not merge" label. What's your plan on this PR?

Hi @isra-fel , the plan was to target the September release, but because of some backend issues, we will postpone it for October. Should I convert the PR to draft, and reactivate it when it is ready to merge?

[isra-fel]

Please do convert it to draft. Thanks! @krivi37