media: Remove debug.h, finalize MediaDebug.h

* Funny rust from 0 AD.

MediaConnection: Review format negotiation mechanism

MediaConnection: Hide connection callbacks

* At this point we want to avoid the user calling the callbacks
in the form of BMediaConnection. Instead we force to use the
BMediaInput and BMediaOutput versions.

MediaConnection: BufferSize should be inherited

* While it's trivial for audio to calculate the buffer size,
it isn't the same for video.

MediaClient: Some more consistency in args order

MediaClient: Add remaining wiring for input/output functionality

* BufferReceived is renamed HandleBuffer.
* Update doc.
* Implement buffer production private methods.

MediaClient: Polish destructors

* Make Release() the only public way to destroy a connection.

MediaClient: Fix style for private methods and other cleanup

* Cleaned up some unneeded callbacks.

Populate media/experimental with future media_kit classes

* Node implementations headers are move into src/kits/media.