refs #7197 - add foreman-prepare-realm man page

(cherry picked from commit 65d46d3072ac182501f0645605ef923f2aa4b0de)
Release 1.7.0-RC2
Automatic commit of package [foreman] minor release [1.7.0-0.2.RC2].
Automatic commit of package [foreman-proxy] minor release [1.7.0-0.2.RC2].
Automatic commit of package [foreman-installer] minor release [1.7.0-0.2.RC2].
Automatic commit of package [foreman-selinux] minor release [1.7.0-0.2.RC2].