[Enhancement] Add additional documentation to Material to help 3rd party libraries know what to expect from renderers

[PureWeen]

Summary

Material visual changes a lot of control types and the Android Context itself. Having a single place where people can see the difference between the base controls and the material controls when using material renderers would be very helpful.

For example on Android the Context gets wrapped with a ContextThemeWrapper so if a 3rd party library has just assumed that the Context == Activity it will crash when using Material Visual