Adding conditionals to check if it's an Atomic host

Introduced "register"  and "when" to check for type of host.  before "common" was failing because it wanted to install packages on atomic.  that's not possible.  so we need to skip that action.  Also, Ansible was trying to configure the firewall on Atomic with firewalld.  firewalld is not installed, so checked for Atomic, if it is, run iptables - if not, use firewalld (assuming the host is fedora, rhel, etc... where firewalld is installed.