Support containerized rolling update

- Update rolling update playbook to support containerized deployments
  for mons, osds, mdss, and rgws
- Skip checking if existing cluster is running when performing a rolling
  update
- Fixed bug where we were failing to start the mds container because it
  was missing the admin keyring. The admin keyring was missing because
  it was not being pushed from the mon host to the ansible host due to
  the keyring not being available before running the copy_configs.yml
  task include file. Now we forcefully wait for the admin keyring to be
  generated before continuing with the copy_configs.yml task include file
- Skip pre_requisite.yml when running on atomic host. This technically
  no longer requires specifying to skip tasks containing the with_pkg tag
- Add missing variables to all.docker.sample
- Misc. cleanup

Signed-off-by: Ivan Font <ifont@redhat.com>