engine: adding gluster_server table and dao operations

A new table 'gluster_server' is added. Currently this will
store the gluster UUID of the server and the table has a
reference field(vds_id) to vds_static table.

All the operations on this table like insert, update and
remover are implemented

Change-Id: I04ba0a7bf1eaa964db731cdfa24ab6875e0b1513
Signed-off-by: Kanagaraj M <kmayilsa@redhat.com>