Draft: VideoPlayerViewController : Re-add support for a11y and for new controls brightness & volume

VideoPlayerViewController : Re-add support for a11y and for new controls brightness & volume , add accessibility to close actionSheet and add implementation to make player visible when VoiceOver is on , add panGesture on brightness slider when voiceOver not activated to slide UISlider from any position and not only slider from thumbImage (didn't put it when voiceOver is activated because it detect the pangesture and can't get updated info level sound)

closes #978 (closed)