Adding foreman-installer man page

It builds fine

http://koji.katello.org/koji/taskinfo?taskID=66648
http://koji.katello.org/koji/taskinfo?taskID=66658

*but* rubygem-logging in F19 is missing rubygem-multi_json dependency. Koji is
picking up rubygem-logging-1.8.1-22.fc19 which has missing dep. I need to look
on it tomorrow.