Remove workaround playbook for disabling iptables about tendrl-ansible

[mbukatov]

Details how to configure firewall are available now: https://github.com/Tendrl/documentation/wiki/Tendrl-firewall-settings

[mbukatov]

Accepting this feature for future upstream release 1.5.5

[mbukatov]

Implementation details, based on description in this issue and today's meeting Discuss peding tendrl-nsible issues and plan:

• introduce new ansible variable configure_firewalld_for_tendrl, available in both tendrl-server and tendrl-storage-node roles
• variable configure_firewalld_for_tendrl is True by default
• when configure_firewalld_for_tendrl is True, tendrl-ansible will try to open ports for tendrl services via firewalld
• when configure_firewalld_for_tendrl is True and firewalld is not running, we will abort the playbook (using assert statement) with explanation for the admin, so that he can decide whether to enable firewalld, open ports for gluster and retry, or if he just configures the firewall himself (which includes an option to have no firewall at all) and retry with configure_firewalld_for_tendrl set to false
• when configure_firewalld_for_tendrl is False, tendrl-ansible will not touch any firewalld setup at all and move all responsibility for firewall setup to the admin (this needs to be clearly communicated to the user)

Moreover we decided to handle firewalld reload in tendrl-ansible and not in postscript of tendrl packages shipping firewalld service files.

[mbukatov]

Resolved by #70, with exception of usage of firewalld service files, which is now tracked by #80