Remove partial rebranding of ubuntustudio packages

Ubuntustudio packages are purged from upstream for branding reasons. It includes a great amount of packages, out of which there exist multiple interrelated dependencies. If somebody is ever interested in working on the branding, then all of them should be rebranded and ported together. Otherwise, it will not be possible to install some of them, which is currently the case with trisquelstudio-menu.

I talked a bit about this with chaosmonk, which agreed that those packages should not be there unless there is some specific maintainer which takes care of all of them and moves trisquel forward as a modern media system.

Also, I am only pushing this to nabia, as they already exist in etiona backport repository.