node: Respond always to OS interrupts (#2479)

* stop node upon receiving SIGTERM or CTRL-Ceven during genesis sleep by setting up interrupt before starting a node

Closes #2434

* call Start, not OnStart when starting a component to avoid:

```
E[09-24|10:13:15.805] Not stopping PubSub -- have not been started yet module=pubsub impl=PubSub
```

being printed on exit

p2p/transport.go

@@ -207,7 +207,11 @@ func (mt *MultiplexTransport) Dial(
 func (mt *MultiplexTransport) Close() error {
 	close(mt.closec)
 
-	return mt.listener.Close()
+	if mt.listener != nil {
+		return mt.listener.Close()
+	}
+
+	return nil
 }
 
 // Listen implements transportLifecycle.