Create custom Automation Peer for MauiButton

[PureWeen]

Description of Change

• Create a MauiButton since we already have a bunch of custom logic inside CreatePlatformView that a user would need to replicate our button. This also lets us create a custom AutomationPeer which you can only do through inheritance
• This lets us remove all the children from the accessibility tree and use the TextBlock as the labelfor the button. Prior to this behavior Narrator would select the button and provide no useful description and would then navigate to the TextBlock inside the Button.

[rachelkang]

LGTM!!! Thanks for figuring this out