[Feature]: Store tenant name in AzureRM context

### Description of the new feature

Would it be possible to return the tenant name (just not its ID) when running Get-AzContext?

The use case is that when you are working with multiple tenants, it's a lot faster to check the name than the ID. The Get-AzContext cmdlet is also a lot faster than the Get-AzTenant for instance, so it would be useful if one wants to make it a part of the prompt as well.

### Proposed implementation details (optional)

_No response_

Start by tracing the Get-AzContext cmdlet and how its AzureRM context is assembled, then compare the available tenant information with Get-AzTenant. Done means Get-AzContext exposes the tenant name as well as the existing tenant ID, with behavior suitable for use in a prompt.

Written by the indexing model from the issue text.