webadmin: add permission splitter to disk profiles

Allow to view and manipulate permissions for disk profile entity within
disk profile subtab (regular permission sub tab flow).

Change-Id: Iefbcc953a2685406ae4883602e00beff0440f1be
Bug-Url: https://bugzilla.redhat.com/1085049
Signed-off-by: Gilad Chaplik <gchaplik@redhat.com>