feat: add support for routing an app to a specified host:port

This is useful when there is a service not managed by Dokku but should be exposed via the Dokku routing layer. As an example, some binaries (consul, nomad, vault) expose web uis, and are traditionally run on the host directly vs in a container.

Closes #4665

plugins/network/triggers.go

@@ -140,6 +140,13 @@ func TriggerNetworkGetProperty(appName string, property string) error {
 	return nil
 }
 
+// TriggerNetworkGetStaticListeners fetches the static listener for the specified app/processType combination
+func TriggerNetworkGetStaticListeners(appName string, processType string) error {
+	staticWebListener := reportStaticWebListener(appName)
+	fmt.Println(staticWebListener)
+	return nil
+}
+
 // TriggerNetworkWriteIpaddr writes the ip to disk
 func TriggerNetworkWriteIpaddr(appName string, processType string, containerIndex string, ip string) error {
 	appRoot := common.AppRoot(appName)