Gitlab ci

Add pytest-workflow tests and enable gitlab-ci integration, including the slurm runner.

.gitlab-ci.yml

@@ -27,7 +27,7 @@ test-sanity:
   stage: sanity
 
 test-dry-run:
-  <<: *slurm_before_script_anchor
+  <<: *before_script_anchor
   script:
     - pytest --keep-workflow-wd-on-fail --basetemp ${BASETEMP} --tag dry-run
   image: lumc/singularity-snakemake:3.5.2-5.15.0