[Cleanup] Split Deferred across Microsoft.Toolkit and Microsoft.Toolkit.Uwp

[michael-hawker]

Describe the problem this feature would solve

When we imported the Deferred events package for the TokenizingTextBox, everything was added to the Uwp package as we needed TypedEventHandlers for the TokenizingTextBox.

Describe the solution

We could move everything put the TypedEventHandlerExtensions into the base Microsoft.Toolkit package which would allow anyone to use the deferred events pattern from our .NET Standard based package.

Describe alternatives you've considered

If we're looking at possibly trying to remove the UWP package as a reference in the above packages, this is clearly a chain across the board (even before this change).

Thoughts?

[michael-hawker]

@pedrolamas if we made your deferred events helpers more accessible in the toolkit would you continue to maintain your existing repo or just make updates here instead?

[pedrolamas]

From what I can see, the Microsoft.Toolkit assembly is set for at least .NET Standard 1.4 compatibility (which sounds very reasonable to me), so I see no point in maintaining both, even with mine being .NET Standard 1.0 compatible.

On one side I don't like to be locked into someone else's release cycle, but having said that, the latest version of my NuGet package seems to be quite stable (it hasn't changed for a while now) so I do think it would be safe to deprecate it and point to the Microsoft.Toolkit assembly once the code moves there!

From that point on, I would then archive my repo and make updates only here. How does that sound?