Switch the code to skelcd-control-openSUSE package

the package will be maintained in this Git repository,
(instead of OBS), all changes should happen here and the usual
Yast tooling should be used (Jenkins CI, rake tasks...)

There are some tricky parts:

- the RPM version is dynamically determined from `*.changes` so I had to tweak the `Rakefile` (maybe later we should add some support to packaging tasks to avoid these workarounds) to create the tarball without version in file name

- the original skelcd package has MIT license (according to `*.spec`) so I replaced `COPYING` by `MIT-LICENSE`

- the package contains just few XML files so I dropped the Yast autotools support and use a simple `Makefile`