feat: add rpc gateway and optimize code

cmd/serverNameExample_gwExample/main.go

@@ -0,0 +1,16 @@
+package main
+
+import (
+	"github.com/zhufuyi/sponge/cmd/serverNameExample_gwExample/initial"
+
+	"github.com/zhufuyi/sponge/pkg/app"
+)
+
+func main() {
+	initial.Config()
+	servers := initial.RegisterServers()
+	closes := initial.RegisterClose(servers)
+
+	a := app.New(servers, closes)
+	a.Run()
+}