Bug#832422: albatross-gtk-theme: broken with GTK3.20

[Jeremy Bicha]

Control: severity -1 serious

I propose that we remove albatross-gtk-theme from Unstable & Bullseye.
A GTK theme that doesn't work with GTK3 isn't very helpful any more.

https://github.com/shimmerproject/Albatross

Thanks,
Jeremy Bicha