Musicpod does not honor minimise, maximise, close button placement

[amugofjava]

I'm a left hander and have my Gnome setup for left handed mouse and the minimise, maximise and close buttons on the left side of the title bar. Musicpod does not honor this setting and always places them to the right.

[Feichtmeier]

Must be a gsetting we need to watch for this one And then place the close button correspondingly Should be possible though as we make a lot of use of gsetting in our settings project

[12people]

This relates directly to this yaru_widgets issue (for which I submitted a PR just today): https://github.com/ubuntu/yaru_widgets.dart/issues/532