backend, db: store additional hosted engine info

New fields for hosted engine, allowing UI display/control of maintenance
operations.  Adds:
  ha_configured - HA is installed on the host
  ha_active - HA is currently running/updating on the host
  ha_global_maintenance - HA global maintenance is enabled according to
                          the host
  ha_local_maintenance - HA local maintenance is enabled on the host

Change-Id: Ib62849ffe0f7392c1feb1f2a0536a23410b58210
Bug-Url: https://bugzilla.redhat.com/1047649
Signed-off-by: Greg Padgett <gpadgett@redhat.com>