[Enhancement] Button - corner radius for all single corners

[Mikilll94]

Summary

Right now Button control has CornerRadius property which is always applied to all corners. It would be nice if there was the possibility to define the corner radius for all single corners.

API Changes

Similar to margin and padding properties there should be a possibility to define corner radius for all corners, like this:

<Button CornerRadius="10,20,10,5"/> 

This will apply a corner radius of 10 to the top left corner, 20 to the top right corner, 10 to the bottom right corner and 5 to bottom left corner.

Intended Use Case

A lot of use cases when creating beautiful UI.

[KSemenenko]

It would be nice to do good rounding management. #7208

[samhouts]

Duplicate of #1814