dal: Refactor VmDaoDbFacadeImpl row mapping

Make VmRowMapper delegate to Vm{Static,Dynamic,Statistics}RowMapper
for suitable fields and remove duplication.

It was necessary to rename some of the columns in the vms and
vms_with_tags views to match those used in vm_static to make the
delegation possible.

Change-Id: Ifa158b5d7a37661cf4c1cc1f01ea4db062a8e11f
Signed-off-by: Martin Betak <mbetak@redhat.com>