Shutdown manager if webhook & metrics server cert-watchers fail

Just recently noticed that the webhook & metrics server are starting certWatchers like this

		go func() {
			if err := certWatcher.Start(ctx); err != nil {
				log.Error(err, "certificate watcher error")
			}
		}()

If the cert-watcher is failing we only log this error and that's it. As soon as the certs are rotated again the servers will use outdated certificates.
If this is somehow covered by a livenessProbe the manager will restart otherwise it won't.

I think we should look into how we can shutdown the manager / restart the binary if one of these cert-watchers fail.

One option might be to ensure the Start func of the servers return an error when the cert-watcher fails.

Start with the certWatcher.Start(ctx) calls in the webhook and metrics server, then trace how those server Start functions are connected to the manager. Determine how a watcher failure should propagate so the manager shuts down or the binary restarts, and verify that failures are no longer only logged.