A Rakefile for Jenkins

so that all the jobs in https://ci.opensuse.org/view/libyui/ can say
"rake osc:sr"

Well, not really, but close:
libyui-test has 3 spec files, so the actual call will be
  PACKAGE=libyui-ncurses rake osc:sr

also notice that we don't use ../libyui/Rakefile
Added a copyright and license notice