[CI] Deploy new version on production using gitlab CI

[novicecpp]

One of our CI wishlist, second checkbox #7958

It still use tag-and-push pattern, or trigger through WebUI, which does not have a beautiful interface like Jenkins, but might be more convenient.

The pipeline would have 3 stages: deploy -> runtest -> checktest, to make sure the newly deployed services are running properly.

To deploy on prod, you need 2 variables:

• DEPLOY_PROD, value is container tag you want to deploy.
• DEPLOY_SERVICE, value is all or service name (REST/TaskWorker/Publisher_schedd/Publisher_rucio)

The main blocker (or not?) is to negotiate with Aroosha, to allow us to deploy REST from CI, like we do on testbed, on production backend cluster. I am not sure if she has any security concern about this.