Add enhanced visual states for Button[Base] that uses commands from MVUX

[dr1rrb]

Common design is to have executing and result visual indicator on a button when you press it.

With MVUX where command support IAsyncCommand we have support for such using ButtonExtensions but is not yet documented (cf. #2434).

Before adding documentation, we should validate the contract (and fix spelling issues).

Requirements:

• Should be declarable in default style of an application to be applied on all buttons
• Should be usable for both on canvas buttons and command-bar buttons
• Should support ability to have an executing state
• Should support ability to show the result of an execution (success or failure)
• In case of failure, should provide access to the exception to customize the UI

Question:

• Name of the extensions class (ButtonExtensions or ButtonBaseExtensions or ???)

  Note: The toolkit is using CommandExtensions. We should probably avoid that name to not cause confusion.

• Should we have multiple visual state groups ("executing/idle" vs result "none/success/failure")
• Should we auto reset the "result" visual state after a given delay, or we rely only on animation for this

  Note: currently we are relying on the Animation so the system will handle pause / start / resume from current state properly in case of multiple executions.