Keyboard support: audio player improvements

Description

Both of the audio players (mobile and TV) don't support the keyboard shortcuts. We should add the ones we can.

Support these shortcuts:

KEYCODE_MEDIA_FAST_FORWARD / KEYCODE_MEDIA_REWIND
KEYCODE_BUTTON_R1 / KEYCODE_BUTTON_L1
KEYCODE_MEDIA_PLAY_PAUSE / KEYCODE_MEDIA_PLAY / KEYCODE_MEDIA_PAUSE / KEYCODE_SPACE
KEYCODE_O / KEYCODE_BUTTON_Y / KEYCODE_MENU
KEYCODE_M /KEYCODE_VOLUME_MUTE
KEYCODE_S / KEYCODE_MEDIA_STOP
KEYCODE_E
KEYCODE_N / KEYCODE_CHANNEL_UP / KEYCODE_BUTTON_R1
KEYCODE_P / KEYCODE_CHANNEL_DOWN / KEYCODE_BUTTON_L1
KEYCODE_VOLUME_DOWN / KEYCODE_VOLUME_UP
KEYCODE_PLUS / KEYCODE_EQUALS / KEYCODE_MINUS

Some refactor may be needed to share the code from VideoPlayerActivity.

⚠ we should not intercept the arrow keys to avoid navigating the views.

Smartphone