Doc: Add a note to clarify how to setup network
Doc: Add a note to clarify how to setup network

Explain how to setup networking in ceph-ansible by adding a note in
README.md.

Signed-off-by: Guillaume Abrioux <30a9df5a0293a6108675377fa1673f7aa713f915@redhat.com>

ceph/ansible-ceph-common