Downstream CI: deploy UMB service using ArgoCD

There is a PoC of deploying of downstream CI manifests using ArgoCD, see the Argo app https://gitlab.cee.redhat.com/tekton/plumbing/-/tree/master/apps/ci

At the moment it syncs everything to the namespace pipelines-ci-tmp

Acceptance criteria
1. Create a new Argo app for UMB service or update CI service to deploy also UMB
2. Swithc Argo app from temporary namespace to the production one