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
- allow to set multiple video to to play and zap to next channel
- display toast on error
- add resizing test
- add a seek bar
- add text and audio tracks picker
- add loader during buffering
- add repeat mode test
- add toggle fullscreen
