- Add docs describing how to connect to th Prometheus UI of a Prometheus
managed app installed on Kubernetes.

- Add a link to this new doc on the development docs index page.

- Add a link to the existing Prometheus metrics docs in the new
Prometheus docs.

- Remove the link to the Prometheus metrics page in the development
docs index page.

- Add link to new doc in Prometheus integrations doc under the
troubleshooting section.