CI: Allow to test changes that might affect release only jobs

This MR allow to test changes in the CI that might affect jobs that are run only on release branches. This is possible to the recent introduction of two new variables in thi CI : TEZOS_DEFAULT_BRANCH and TEZOS_DEFAULT_NAMESPACE and modifying the jobs to publish docker images on dockerhub.

To test, the reviewer should specify the two above variables as follow :

  TEZOS_DEFAULT_BRANCH: "abate@test-release"
  TEZOS_DEFAULT_NAMESPACE: "tezos"

This will have the effect of allowing all jobs that are normally run only on master in the current branch. The namespace can also be changed when pushing ( or while proposing and MR ) on a different namespace.

I refactored the docker authentication to make it possible to push on gitlab and dockerhub depending if we're testing, or we are pushing on a release branch.

I changed the script in TAG_NAME because it was not working as expected.

To comply with gitlab strict naming convention, now tags strictly use _ instead of - . This should not change anything for docker images, since arch specific tags are hidden in the manifest.

The publish:documentation now detects if we are pushing on a protected branch, and does not attempt to push documentation in this case ( otherwise it would fail with auth denied ).

Notice that the pipeline is a release pipeline and not a normal pipeline. The last commit should be removed before merging.

For extra testing, you should also try a branch without the -release string .