* feat(controller): New health service and server
This change also implements a new listener purpose, `ops`.
`ops` (short for operations) is a new listener purpose that is
responsible for serving Boundary's operations endpoints, like health
and possibly metrics.
At Startup: `ops` listeners get configured as late as possible to catch
any errors with the startup process;
At Shutdown: If the health endpoint has been set-up, we introduce a
configurable delay in the process. This is to enable the health endpoint
to report unhealthy for that amount of time. `ops` listeners are also
the last listeners to be shutdown.