Add epel repo for el distros

Default: add, deactivable. EPEL contains some Ceph dependencies.

Signed-off-by: Alexandre Marangone <alexandre.marangone@inktank.com>
handle different package names el, fc vs deb

Signed-off-by: Alexandre Marangone <alexandre.marangone@inktank.com>
create mon data dir before calling ceph-mon

Signed-off-by: Alexandre Marangone <alexandre.marangone@inktank.com>
add gitbuilder key for rpm

Signed-off-by: Alexandre Marangone <alexandre.marangone@inktank.com>