restructured the project to comply community guideline, for others check release note

internal/server/instance.go

@@ -0,0 +1,25 @@
+package server
+
+var proxyServer, apiServer *server
+
+func InitProxyServer(opt Options) *server {
+	if proxyServer == nil {
+		proxyServer = NewServer(opt)
+	}
+	return proxyServer
+}
+
+func InitAPIServer(opt Options) *server {
+	if apiServer == nil {
+		apiServer = NewServer(opt)
+	}
+	return apiServer
+}
+
+func GetProxyServer() *server {
+	return proxyServer
+}
+
+func GetAPIServer() *server {
+	return apiServer
+}