Create a single deployment token for all chat solution projects

Using GitLab, we cannot have a group level deploy token. It’s still an open issue for GitLab
https://gitlab.com/gitlab-org/gitlab-ce/issues/45066
https://gitlab.com/gitlab-org/gitlab-ce/issues/47767
https://gitlab.com/gitlab-org/gitlab-ce/issues/45067

Deploy Tokens work for a single project only.
https://docs.gitlab.com/ee/api/deploy_key_multiple_projects.html

Not sure if we can have a way around but needs to be investigated. We'll use a deploy user privileges meanwhile exposing all of our chat solution repositories with read-only access at the moment.