docs: Add debugging guide for the media subsystem

Provide a guide for developers on how to debug code with a focus on the
media subsystem. This document aims to provide a rough overview over the
possibilities and a rational to help choosing the right tool for the
given circumstances.

Signed-off-by: Sebastian Fricke <sebastian.fricke@collabora.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20241028-media_docs_improve_v3-v3-2-edf5c5b3746f@collabora.com