[DOC] Suggestion: Rename Subgroup to Basegroup in the settings

[kludikovsky]

In the FE-usergroup there is a defintion of subgroup a group belongs to.

This term implies somewhat the group itself is split into those subgroups and itself is a supergroup of the subgroups. Which actually is not the case.

In reality the 'subgroup' is a group this group inherits their rights.

I would therefor suggest to rename the item from 'subgroup' to 'basegroup' which would better describe it function, as the group is based on the basegroups rights.