Allow shuffle and repeat all
Most music players available allow this, and it's a feature I use a lot personally and would like to see in gnome-music.
As a proposed implementation I would separate the shuffle and repeat features into two distinct properties, which would also simplify and clarify the parts of the codebase which handle repeat/shuffle logic (at least in my opinion).
I have this done in a fork already, but I'll wait for feedback on whether the feature/implementation of the feature would be accepted before sending a PR.