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/PropertySheet.props

@@ -1,16 +1,16 @@
-<?xml version="1.0" encoding="utf-8"?>
-<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-  <ImportGroup Label="PropertySheets" />
-  <PropertyGroup Label="UserMacros" />
-  <!--
-    To customize common C++/WinRT project properties: 
-    * right-click the project node
-    * expand the Common Properties item
-    * select the C++/WinRT property page
-
-    For more advanced scenarios, and complete documentation, please see:
-    https://github.com/Microsoft/xlang/tree/master/src/package/cppwinrt/nuget 
-    -->
-  <PropertyGroup />
-  <ItemDefinitionGroup />
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ImportGroup Label="PropertySheets" />
+  <PropertyGroup Label="UserMacros" />
+  <!--
+    To customize common C++/WinRT project properties: 
+    * right-click the project node
+    * expand the Common Properties item
+    * select the C++/WinRT property page
+
+    For more advanced scenarios, and complete documentation, please see:
+    https://github.com/Microsoft/xlang/tree/master/src/package/cppwinrt/nuget 
+    -->
+  <PropertyGroup />
+  <ItemDefinitionGroup />
 </Project>