v2_tx_live_player library

1. live_flutter_plugin package
2. documentation
3. v2_tx_live_player.dart

live_flutter_plugin package

1. Libraries
2. manager/tx_audio_effect_manager
3. manager/tx_beauty_manager
4. manager/tx_device_manager
5. v2_tx_live_code
6. v2_tx_live_def
7. v2_tx_live_player
8. v2_tx_live_player_observer
9. v2_tx_live_premier
10. v2_tx_live_pusher
11. v2_tx_live_pusher_observer
12. widget/v2_tx_live_video_widget