The desired number of mons could change depending on the number of nodes in a cluster.
For example, three mons would be the min number of mons in a production cluster with at
least three nodes. If there are five or more nodes, the number of mons could increase
to five in order to increase the failure tolerance to two nodes.

This is accomplished by a new setting in the cluster CRD preferredCount. If the number
of hosts exceeds preferredCount, more mons are added to quorum. If the number
of hosts drops below the preferred count, the operator would reduce the quorum size to
the smaller desired count.
Signed-off-by: travisn <tnielsen@redhat.com>