add testing of cutter

[sebhoerl]

Often, we cut out smaller simulations from the generated scenarios. It would be interesting to add a stage to the pipeline that "test cuts" out a small region, for instance Melun, and then tests that the simulation can be run. At the same time, it would be interesting to add this to the unit tests in a generic way.

• Add stage for cutting out and running Melun
• Add test that cuts and runs the test scenario