As a Data Center administrator I want the /status endpoint to return ERROR if Sidecar is not running so the load balancer can detect the node as being unhealthy

Currently, when Sidecar is down for any reason, any access (via git commands or via the browser) to repositories results in a RepositoryOfflineException, arguably rendering the node useless for serving the vast majority of requests.

As such, requests should not be routed to a node in such a state, and for a load balancer to detect that, the /status endpoint should return ERROR when Sidecar is not running (or repositories are offline for any other reason).