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/MainPage.cpp

@@ -0,0 +1,20 @@
+#include "pch.h"
+#include "MainPage.h"
+#if __has_include("MainPage.g.cpp")
+#include "MainPage.g.cpp"
+#endif
+
+#include "App.h"
+
+using namespace winrt;
+using namespace Windows::UI::Xaml;
+
+namespace winrt::videoplayer::implementation
+{
+    MainPage::MainPage()
+    {
+        InitializeComponent();
+        auto app = Application::Current().as<App>();
+        ReactRootView().ReactNativeHost(app->Host());
+    }
+}