Blender Git Loki

Fix T76711: override data-blocks could be renamed in the outliner

Overriding datablock should never have an editable name.

This also moves the check for linked/overridden datablocks above the
check for master-collection (otherwise a linked/overriden collection
could still be renamed)

Maniphest Tasks: T76711

Differential Revision: https://developer.blender.org/D7718