Implement FlowDirection property in ViewHandlers

[jsuarezruiz]

Description of Change

• Implement FlowDirection property in ViewHandlers.
• Don't force the platform to LTR. If the FlowDirection matches the windows FlowDirection then don't set anything on the native platform

Platforms Affected

• Core
• iOS
• macOS
• Android
• Windows

PR Checklist

• Targets the correct branch
• Tests are passing (or failures are unrelated)
• Targets a single property for a single control (or intertwined few properties)
• Adds the property to the appropriate interface
• Avoids any changes not essential to the handler property
• Adds the mapping to the PropertyMapper in the handler
• Adds the mapping method to the Android, iOS, and Standard aspects of the handler
• Implements the actual property updates (usually in extension methods in the Platform section of Core)
• Tags ported renderer methods with [PortHandler]
• Adds an example of the property to the sample project (MainPage)
• Adds the property to the stub class
• Implements basic property tests in DeviceTests

[rachelkang]

Text is not getting rendered as RTL

[rmarinho]

I found a couple of issus, some controls don't support RTL.

• Starting app with Hebrew (RTL language) doesn't show the app in RTL on iOS
• Forcing RTL on my android Device and starting the app doesnt show the sample app with RTL on

[PureWeen]

@rmarinho logged your findings here
#2255