Switch functional tests to use cephx; Tests should really
align to default configuration, which is to have cephx
enabled for a deployment.
Updated README to be a little simpler, and default to
Xenial rather than Trusty.
Added proper Ceph icon.
Drop layer dependency on ceph-base - it brings in loads
of stuff we don't need.
Tidy config.yaml to drop duplicate ceph-public-network.
Depends-On: Ied8d5306ab77b8e68efd0a8e5df4087a067f0367
Change-Id: I4ab5438db93ae613e9232ca42df1c23614e212e6