core, webadmin: Add host# and vm# to cluster tab

In webadmin add an ability to see the count of VMs and Hosts for
a cluster

Change-Id: I9935c67db2a88960cd721aec4bfd71e70c9b4f57
Bug-Url: https://bugzilla.redhat.com/1084120
Signed-off-by: lzelkha@redhat.com <lzelkha@redhat.com>