aaa: Introducing  attach_user_to_su_role

1. Introducing a function to attach role for user on system object
2. Removed attach_user_to_su_role
3. Moved generation of permission id to DB (changed manage domains code)
4. Introduced ovirt-engine-role.sh script to add role to authz user.

Change-Id: I7c6e25aa5f187ae06bd105f5493acacda355730a
Signed-off-by: Yair Zaslavsky <yzaslavs@redhat.com>
Signed-off-by: Alon Bar-Lev  <alonbl@redhat.com>