[Feature Request] Create az repos tag create command

**Is your feature request related to a problem? Please describe.**
If you are not an Azure Repos expert like me, it takes a while to find out that you need to use this command.
Another reason why a separate command would be good is the fact that you cannot provide a description for the tag, which might be because "ref create" is also used for branching which has no description.

**Describe the solution you'd like**
Create az repos tag create command