Release staging pipeline should tag pipeline runs with release storage account staging container names

[lbussell]

The .NET release staging pipeline adds several tags to each build. Examples from a recent staging pipeline run:

• Channel - 10.0
• Release - 10.0.*
• Runtime - 10.0.*-servicing.12345.123
• SdkOnly
• BAR - 123456
• Container - stage-1234567

We should do the same with the dotnet-docker release staging pipeline. This will enable simpler coordination between the .NET release pipelines and the .NET containers release pipelines.