Add distro yamls.

Should be no harm to get these in now.

To run on all distros the distros dir should just be symlinked in
the folder that also contains tasks, IE:

suites/ceph-deploy/fs

Or make a distro's folder and symlink individual distro's so you
have:

suites/ceph-deploy/fs/distros/centos.yaml
suites/ceph-deploy/fs/distros/fedora.yaml
suites/ceph-deploy/fs/distros/rhel.yaml
suites/ceph-deploy/fs/distros/ubuntu.yaml

etc...

Signed-off-by: Sandon Van Ness <sandon@inktank.com>