Remove the gui's binary language files from the repo

[Torsten]

Hello,

until now, the binary translation files (.qm) for the gui are contained
in the repo together with their sources (.ts). For generating the
binaries during the build process, the "qt linguist tools" (in
particular the tool "lrelease") must be installed.

I would like to know if this additional requirement would be okay in
order to remove the binary language files from the repo.

Torsten