Changed from specifying ports to services to open

Firewalld playbook now specifies specific services to enable rather than
the ports that they typically use. This increases readability and
clarity in the playbook.
Added comments for port 8443 to playbook

Comments have been added to clarify the purpose of opening port 8443.
This should improve clarity.
Merge pull request #85 from ausaccessfed/feature/firewalld-services

Specified services instead of ports for firewalld tasks
Resolves #75