feat: use centralised terraform module renovate configuration

Make use of the centralised renovate configuration introduced by uis/devops/renovate-config!204 (merged) so that downstream modules have one fewer thing to keep in sync.

Addresses uis/devops/infra/gitlab-bots-deployment#79 at the same time since the centralised configuration includes automerge support.

Closes uis/devops/renovate-config#33 (closed)

Closes uis/devops/infra/gitlab-bots-deployment#79