core: disk profile commands and queries

commands: create/update/delete disk profile
queries: GetDiskProfileById, GetAllDiskProfiles, GetDiskProfilesByStorageDomainId.

Change-Id: I0d871f1603671bc14ce88c68f85638b1af67f5e1
Bug-Url: https://bugzilla.redhat.com/1085049
Signed-off-by: Gilad Chaplik <gchaplik@redhat.com>