Create an entry to the single release-tools pipeline from Chatops

As we move functionality in the deployer pipeline to the release-tools pipeline #1395 (closed) we should create an entry-point from Chatops, so we can do manual deploys or re-deploys to environments.

Additionally, it would be good to use our current https://gitlab.com/gitlab-org/release-tools/blob/master/config/release_managers.yml file for permissions since right now deploying an existing artifact is wide open to members of the Chatops project.