[Azure CDN] Cmdlets for Multi-Origin & Private Link Functionality

[jorinmejia]

Description

This PR brings new and modified cmdlets for the Multi-Origin and Private Link functionality for the Azure CDN service.

Checklist

• I have read the Submitting Changes section of CONTRIBUTING.md
• The title of the PR is clear and informative
• The appropriate ChangeLog.md file(s) has been updated:
  • For any service, the ChangeLog.md file can be found at src/CDN/CDN/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
• The PR does not introduce breaking changes
• If applicable, the changes made in the PR have proper test coverage
• For public API changes to cmdlets:
  • a cmdlet design review was approved for the changes in this repository (Microsoft internal only)
  • the markdown help files have been regenerated using the commands listed here

Design Review

[markcowl]

/azp run

[azure-pipelines]

No pipelines are associated with this pull request.

[markcowl]

/azp run

[azure-pipelines]

No pipelines are associated with this pull request.

[dingmeng-xue]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 3 pipeline(s).

[dingmeng-xue]

@jorinmejia , test case is failed. Please check the log
https://dev.azure.com/azure-sdk/29ec6040-b234-4e31-b139-33dc4287b756/_apis/build/builds/568042/logs/33

[jorinmejia]

@dingmeng-xue / @isra-fel can I please get a follow up review for this PR?

[isra-fel]

And please remove the temp SDK packages tools/LocalFeed/Microsoft.Azure.Management.Cdn.4.3.0-preview.nupkg and tools/LocalNugetFeed. I don't think you are using them anymore.