Resolve "Display track title in window title"

Related issue: #359

So this should update the title to "FW - SONGNAME" everytime a new song is played. I first wanted to add the artist name but tabs are not that large, right ?

Not sure how to test that, is there any easy way to do it ?

This Merge Request includes:

• Tests
• A changelog fragment (cf https://docs.funkwhale.audio/contributing.html#changelog-management)