core+ui: Added 5 new events to event notifier

Added new host performance events to event notifier:
 - Host memory usage exceeded defined threshold
 - Host network usage exceeded defined threshold
 - Host cpu usage exceeded defined threshold
 - Host swap memory usage exceeded defined threshold
 - Host free swap memory is under defined
threshold

Change-Id: Ie6e7949cae8729c38f1cacc36e39b51b53559f13
Signed-off-by: Ofri Masad <omasad@redhat.com>