jobs: Put groovy code to update GitLab commit status in an include file

This code snippet is used in numerous Jenkins pipelines so better deduplicating it.

cc @teams/sysadmin (<- @anlambert, @vlorentz just so you know, this then appears in the todo in the upper right corner to the highlighted group/person)

---

Migrated from D9003 (view on Phabricator)

jobs/templates/includes/update-gitlab-commit-status.groovy.j2

+failure {
+  updateGitlabCommitStatus name: 'jenkins', state: 'failed'
+}
+success {
+  updateGitlabCommitStatus name: 'jenkins', state: 'success'
+}
+aborted {
+  updateGitlabCommitStatus name: 'jenkins', state: 'canceled'
+}