Prompt for additional codec installation

[moqmar]

Prerequisites

• I have searched open and closed issues for duplicates.

Feature

Is your feature request related to a problem? Please describe.
Most of my music are .m4a files, but unfortunately I can't play this common file format using this application on a newly set up elementary OS 6 (early access) system. Everything works after installing the gstreamer1.0-libav package.

Describe the solution you'd like
Add gstreamer1.0-libav as a dependency - people expect a music player to be able to play most of their music, so I think this should definitively be a dependency, or at least pre-installed on elementary OS.

Existing work
See gstreamer1.0-libav

Describe alternatives you've considered
Use another music player, or install gstreamer1.0-libav manually

[tintou]

Ubuntu itself doesn't do it and provide a checkbox to install it at system installation time as it has plugins that are not usable legally in all area.

[danirabbit]

Started a discussion here: elementary/initial-setup#91

I guess theoretically though there should be a gstreamer interface for requesting codec installation though right?

[danirabbit]

It looks like music supposedly should handle additional codec installation already, but this is likely broken. David has been working on adding a dbus interface to AppCenter for codec installation for Videos. So it makes sense that we would use that here as well when it's ready