Make fedora-packager-kerberos subpackage
    
    Breaks out the kerberos configs into own subpackage so that users
    who want to connect to kerberos but not install all the depenencies
    of `fedora-packager` can do that.
    
    Fixes https://pagure.io/fedora-packager/issue/152
    
    Signed-off-by: Dusty Mabe <dusty@dustymabe.com>