ci(gitlab-ci): use templates from a common repository

6 jobs for branch/default in 3 minutes and 17 seconds (queued for 11 minutes and 55 seconds)
Name Stage Failure
failed
safety Lint
| package                    | installed | affected                 | ID       |
+============================+===========+==========================+==========+
| waitress | 1.4.4 | <2.1.1 | 46436 |
+==============================================================================+
ERROR: InvocationError for command /builds/cubicweb/cubes/ckeditor/.tox/safety/bin/safety check (exited with code 255) (exited with code 255)
___________________________________ summary ____________________________________
ERROR: safety: commands failed
Cleaning up file based variables
ERROR: Job failed: command terminated with exit code 1