Open firewall port 3300 for ceph monitors v2 protocol

In addition port 6789, open port 3300 too for ceph monitors.
As per the Ceph documentation:

"Ceph monitors now bind to IANA-assigned port 3300 (ce4h or 0xce4)
for the new v2 protocol, while also binding to the old default
port 6789 for the legacy v1 protocol."

Change-Id: Ib9a69cc9379e84a47bdc00a175ee33bfac4119eb
Closes-Bug: #1820359

docker/services/ceph-ansible/ceph-mon.yaml

@@ -101,4 +101,5 @@ outputs:
             '110 ceph_mon':
               dport:
               - 6789
+              - 3300
         - {}