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: I3aa24e6781fb0efcd539a44a0adf2aefb897c3d1
Topic: AAA
Signed-off-by: Yair Zaslavsky <yzaslavs@redhat.com>
Signed-off-by: Alon Bar-Lev <alonbl@redhat.com>