Decouple ServiceUpdate to ServerUpdate to be more native (#8138)

The change now is to ensure that we take custom URL as
well for updating the deployment, this is required for
hotfix deliveries for certain deployments - other than
the community release.

This commit changes the previous work d65a2c6725
with newer set of requirements.

Also deprecates PeerUptime()

cmd/service.go

@@ -26,10 +26,8 @@ import (
 type serviceSignal int
 
 const (
-	serviceStatus  serviceSignal = iota // Gets status about the service.
-	serviceRestart                      // Restarts the service.
+	serviceRestart serviceSignal = iota // Restarts the server.
 	serviceStop                         // Stops the server.
-	serviceUpdate                       // Updates the server.
 	// Add new service requests here.
 )