Update README
Add Vagrantfile, example settings file, and Ansible playbook
Point out that settings.yml is required
Use a more concise settings.xml example
Use parallel provisioning with Ansible

Rationale explained in README, as seen in
https://docs.vagrantup.com/v2/provisioning/ansible.html.
foo
Only add repos, not install ceph or ceph-deploy on RHEL/CentOS
Remove superfluous dead block
Add libvirt private networks, update README
Remove charlie
Fix network configuration
Properly install package signing keys

Not only install the Ceph release key, but also the autobuild key
(required for ceph-deploy) and the EPEL 6 package signing key.

Also, use Ansible's rpm_key module instead of shell with "rpm
--import".
Fix task name

We're installing several package repos, not just the ceph one.
Enable NTP daemon
Clean up package installation on RHEL/CentOS
Install yum/apt cache
Disable yum fastestmirror plugin