RFC-167: enforce monitoring
Created by: flying-robot
This introduces a PreMountGrafanaHook
that is exposed from the internal app
package via the external one, and hooked into via the enterprise Init
component.
The Grafana endpoints are handled via our REST API, and right now in the event of an error there's a pretty sparse plaintext page that gets rendered; this does the same, and changes the error message to be license-based but I expect later work will change this UX.
fixes https://github.com/sourcegraph/sourcegraph/issues/14030