core, db: disk profile: handle attach/detach

Attach: create disk profile for new storage domain
in pool (attach/create)

Detach: remove qos id from disk profiles of detached
storage domain

Change-Id: I29aaf7b0b537f0b80b91b09e025e9487bbb69c2d
Signed-off-by: Gilad Chaplik <gchaplik@redhat.com>