Weblate Permissions: set Viewers group for every user (sysadmin#17338)

Weblate documentation tells, that every normal User is in Users
and Viewers group. This patch removes removes the GroupDBQuery, that was
only added to hide the unstrict usage of Viewers group for our userbase.

https://docs.weblate.org/en/latest/admin/access.html#list-of-groups
https://docs.weblate.org/en/latest/admin/access.html#autogroup