Remove unused instructions from CI configuration

.compose-gitlab-ci.yml

 variables:
   GIT_STRATEGY: clone
   GIT_SUBMODULE_STRATEGY: recursive
-  DIRECTORY: "/beegfs/agullo/compose/"  # Storage directory on PlaFRIM.
 
 stages:
   - build
   - deploy                      # Create the report and deploy the Gitlab pages.
 
-before_script:
-  - mkdir -p public/
-
 buildrawlatex:
   # We recommend NOT to use this feature and only rely on org.
   # However, it is still possible to handle raw latex files,