core: Add an audit log entry when number of LVs on a domain exceeded max

When creating a new image/snapshot on a block domain, if the number of LVs
on this domain exceeded the maximum value defined in the config, an audit
log entry will be added to warn the admin

Change-Id: Ie701a4b622b4f93690020922f96279d28903abc8
Signed-off-by: Tal Nisan <tnisan@redhat.com>
Bug-Url: https://bugzilla.redhat.com/1015186