[Storage] Support Point in Time Restore

[blueww]

Description

The design in https://github.com/Azure/azure-powershell-cmdlet-review-pr/issues/466
Almost pass review

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/{{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
• 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

[blueww]

@wyunchi-ms
The test failed with 214 network cases failed.
But seems I don't have any change on this. And the cases pass on my local machine.
Would you please help to look how to fix it?

Following is error log:

System.Management.Automation.RuntimeException : Test failed due to a non-empty error stream. First error : PowerShell Error Record: The specified module 'D:\a\1\s\artifacts\Debug\Az.Sql\Az.Sql.psd1' was not loaded because no valid module file was found in any module directory. [D:\a\1\s\build.proj]
Exception:System.IO.FileNotFoundException: The specified module 'D:\a\1\s\artifacts\Debug\Az.Sql\Az.Sql.psd1' was not loaded because no valid module file was found in any module directory.