media: doc: properly format ToC headings

"class:: toc-title" was a workaround for older Sphinx versions that are
no longer supported.

The canonical way to add a heading to the ToC is to use :caption:.
Do that.

Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: linux-media@vger.kernel.org
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20231027081830.195056-10-vegard.nossum@oracle.com

media: docs: */media/index.rst: don't use ReST doc:`foo`

The :doc:`foo` tag is auto-generated via automarkup.py.
So, use the filename at the sources, instead of :doc:`foo`.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

media: docs: add glossary.rst with common terms used at V4L2 spec

Add a glossary of terms used within the media userspace API
documentation, as several concepts are complex enough to cause
misunderstandings.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

media: docs: add cros-references to the other media guides

In order to make easier for people to navigate between the
three media guides, add cross-references between them

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

media: docs: add GPLv2 for uAPI guide

Newer uAPI docs should be dual-licensed with both GPL
and GFDL. Add a text adding the GPLv2 license text there,
in order to be coherent with the included docs.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

media: docs: move copyrights to the end and update them

The copyright info is not the most valuable information
there. Move them to the end.

While here, change the copyright to cover up to this
year (2020).

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

media: docs: add an uAPI chapter for driver-specific stuff

There are some uAPI stuff that are driver-specific. Add them
to the main media uAPI body.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

media: docs: move uAPI book to userspace-api/media

Since 2017, there is an space reserved for userspace API,
created by changeset 1d596dee3862 ("docs: Create a user-space API guide").

As the media subsystem was one of the first subsystems to use
Sphinx, until this patch, we were keeping things on a separate
place.

Let's just use the new location, as having all uAPI altogether
will likely make things easier for developers.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>