By setting GRAPH_LDAP_GROUP_CREATE_BASE_DN a distinct subtree can be
configured where new LDAP groups are created. That subtree needs to be
subordinate to GRAPH_LDAP_GROUP_BASE_DN. All groups outside for
GRAPH_LDAP_GROUP_CREATE_BASE_DN are considered read-only and only groups
below that DN can be updated and deleted.
This is introduced for a pretty specific usecase where most groups are managed
in an external source (e.g. a read-only replica of an LDAP tree). But we still
want to allow the local administrator to create groups in a writeable subtree
attached to that replica.
