Return Service errors

Additionally, removed the context that gets passed into the Services but isn't used in one of them. The websockets APIs also don't have any use for context.

app.go

@@ -125,7 +125,7 @@ func NewApp(request NewAppRequest) (*App, error) {
 	}
 
 	wsWriter := &ws.WebsocketWriter{Conn: conn}
-	service := newService(wsWriter, ctx, httpClient)
+	service := newService(wsWriter)
 	state, err := newState(httpClient, request.HomeZoneEntityId)
 	if err != nil {
 		return nil, err