Add TextInput property so users can enable/disable if they want tapping outside on an input field to close the keyboard

[PureWeen]

Description

Allow users the ability to toggle closing the software keyboard when the user clicks outside of an input field. This was the default behavior in Xamarin.Forms but we removed this behavior because the implementation on Android broke accessibility. We can implement this on Android in such a way that doesn't break accessibility. This is a high requested item and something important to Xamarin.Forms migration.

Related: #12002

Intended Use-Case

• Implemented at Controls Level

<Page HideSoftInputOnTapped="true" x:Name="page" />

[ghost]

We've moved this issue to the Backlog milestone. This means that it is not going to be worked on for the coming release. We will reassess the backlog following the current release and consider this item at that time. To learn more about our issue management process and to have better expectation regarding different types of issues you can read our Triage Process.