added firewalld module

update with feedback from pull request
added version checking, doesn't work in older versions
added try/catch around .connected call
Merge branch 'maxamillion/firewalld' of https://github.com/maxamillion/ansible into maxamillion-maxamillion/firewalld
Moving firewalld module from net_infra to system
More housekeeping

* Modified version_added strings in recent modules
* Added firewalld inclusion to the CHANGELOG