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/ios/VideoPlayer/AppDelegate.h

@@ -7,9 +7,10 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
+#import <React/RCTBridgeDelegate.h>
 #import <UIKit/UIKit.h>
 
-@interface AppDelegate : UIResponder <UIApplicationDelegate>
+@interface AppDelegate : UIResponder <UIApplicationDelegate, RCTBridgeDelegate>
 
 @property (nonatomic, strong) UIWindow *window;