Drop Channels feature?

[Jeremy Bícha]

Ubuntu's default video app, Totem, includes a Channels tab with 3 web video providers:
- Apple Movie Trailers
- Euronews
- Rai.tv

Screenshot attached.

I recommend that we disable this feature because
- These are somewhat obscure video sources

- It can be unexpected to parents, school administrators, etc. for this app to be able to view web content

- Perhaps most importantly, none of these 3 sources seemed to work today in my clean Ubuntu 23.04 install.
+ Apple Movie Trailers worked after I installed the additional media support which is offered in the Ubuntu installer (ubuntu-restricted-addons which specifically installs gstreamer1.0-libav)
+ Based on the errors shown in my terminal, it looks like Euronews either changed their API or it's no longer available.

- If these channels can be broken and we aren't getting bug reports, are people actually even using this feature?

Implementation
--------------
This feature is enabled by some plugins shipped in totem's src/plugins . They can be disabled by the meson build.

Also, totem depends on grilo-plugins-0.3-base which provides supporting files. None of the plugins works if that dependency is removed.

We would then also need to patch Totem to no longer show the Channels page in the Totem app.

[Sebastien Bacher (seb128)]

The idea was also suggested upstream on https://gitlab.gnome.org/GNOME/totem/-/issues/355

[Sebastien Bacher (seb128)]

The plugins are indeed not working, I've disabled them for mantic now
https://launchpad.net/ubuntu/+source/grilo-plugins/0.3.16-1.1ubuntu3

One point from upstream is that the channel tab can list local content over dlna which might still we wanted, also removing the channel tab more of an UI change that could impact documentation so that will do for this cycle