iOS Swift Conversion (#2527)

Converts iOS implementation from Objective-c to Swift

# During the conversion process some updates to the code structure were also made
- Modularize codebase from single file to smaller focused files
- Untangled large nested IF statements
- Added more null checks, since Swift is more strict with null pointers
- Added property to allow for decoding of local video sources with self contained key for offline playback
- Updates example apps to test react-native 0.63.4 and uses auto native dependency imports for android and ios

examples/basic/windows/VideoPlayer/App.xaml

@@ -1,8 +1,8 @@
 <react:ReactApplication
-    x:Class="VideoPlayer.App"
+    x:Class="videoplayer.App"
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-    xmlns:local="using:VideoPlayer"
+    xmlns:local="using:videoplayer"
     xmlns:react="using:Microsoft.ReactNative">
     <Application.Resources>
         <XamlControlsResources xmlns="using:Microsoft.UI.Xaml.Controls" />