Sampler: Delete files that are not used
When running the SAMPLER, it might run thounds of OPAL simulations. In each directory we will then have files like *.lbal, *.out, etc., that might not be needed. Since on clusters you sometimes / normally have quotas on number of files, I think it would make sense that we add an option to the SAMPLER command where we can specify which files to delete directly after one simulation.