retro: Split CoreCallbackHandler in domain specific handlers

CoreCallbackHandler replaced by VideoHandler, AudioHandler and InputHandler.
Engine: Delegate input handling to ControllerHandler
Core: No more require callback handlers to construct
AudioDevice: Implements AudioHandler
Display: Implements VideoHandler
VideoHandler: Rename video_refresh_cb() to render()
AudioHandler: Rename methods

Rename audio_sample_cb() to play_sample().
Rename audio_sample_batch_cb() to play_batch().
InputHandler: Rename methods

Rename input_poll_cb() to poll(). Rename input_state_cb() to get_state().