Revert "Make resource_group mandatory on a CE since the CE collector uses it  (SOFTWARE-3789)"
Revert "Make resource_group mandatory on a CE since the CE collector uses it  (SOFTWARE-3789)"

This reverts commit fd853edcb604da9be1d24648c8e79d355b475082.

matyasselmeci/osg-configure,matyasselmeci/osg-configure,opensciencegrid/osg-configure,opensciencegrid/osg-configure