This MR updates the .gitlab-ci.yml file to bring it up to date with the latest version of fsl/fsl-ci-rules. A new fsl-ci-test stage has been added, which is used to run pyfeeds unit tests, for those projects which have them.
The fsl_mrs repository already has its own unit testing infrastructure, so the new fsl-ci-test stage is not needed for fsl_mrs. But unfortunately the stage still has to be defined, otherwise gitlab will complain.
The fsl-ci-test stage can however be disabled, by setting a CI variable called FSL_CI_SKIP_TEST=1. I've taken the liberty of setting this variable on this repository.