refactor: remove use of IP and PORT files from core-post-deploy plugin

plugins/network/src/triggers/network-config-exists/network-config-exists.go

@@ -0,0 +1,22 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+
+	network "github.com/dokku/dokku/plugins/network"
+)
+
+// write the ipaddress to stdout for a given app container
+func main() {
+	flag.Parse()
+	appName := flag.Arg(0)
+
+	if network.HasNetworkConfig(appName) {
+		fmt.Fprintln(os.Stdout, "true")
+		return
+	}
+
+	fmt.Fprintln(os.Stdout, "false")
+}