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

.gitlab-ci-extended.yml

+---
+# follow this doc to extend the already existing jobs:
+# https://docs.gitlab.com/ee/ci/yaml/includes.html#overriding-external-template-values
+
+# as a reminder the existing jobs are located here:
+# https://forge.extranet.logilab.fr/open-source/gitlab-templates/
+
+# or simply add more jobs here if you need them (use the already existing stages)
+
+# /!\ remember to uncomment the include in the .gitlab-ci.yml /!\

MANIFEST.in

@@ -6,3 +6,5 @@ recursive-include cubicweb_rqlcontroller/data *.gif *.png *.ico *.css *.js
 recursive-include cubicweb_rqlcontroller/i18n *.po
 recursive-include cubicweb_rqlcontroller/wdoc *
 exclude .cube-doctor.yml
+exclude .gitlab-ci.yml
+exclude .gitlab-ci-extended.yml