Backup/Restore Managed Instance (#1428)

* Enabled backup to and restore from URL

* Created RPC, but when process tries to load Microsoft.Azure.Storage.Blob.dll, it crashes

* Added create shared access token

* Code refactor

* Minor changes

* Changed RPC path

* Moved createSas RPC to the newly created BlobService, fixed PR comments

* Added sas expiration date parameter to the RPC

* Added copyright headers

* Removed ConnectionInstance property from BlobService

* Removed unhelpful comment

* Removed unused using statements

* Changed copy/paste comments

* Disposable objects fix

* Small formatting fix

* Changed backup to/restore from url supported device types

* Added backup to url integration test

* Created restore integration test. Test are now getting azure blob params from env variables instead of file.

* Culture invariant epiration date param, fixed comment, and typo

* Updated headers

* PR comments fix

* Changed supported device type logic

* string localization fix

* String formatting fix

* build failure fix

* Typo

* Updated supported restore device types

Packages.props

@@ -40,5 +40,6 @@
 		<PackageReference Update="xunit.runner.visualstudio" Version="2.4.1" />
 		<PackageReference Update="Microsoft.NET.Test.Sdk" Version="16.6.1" />
 		<PackageReference Update="Microsoft.SqlServer.TransactSql.ScriptDom.NRT" Version="1.2.10202.1" />
+		<PackageReference Update="Azure.Storage.Blobs"  Version="12.10.0"  />
 	</ItemGroup>
 </Project>