refactor: rewrite network plugin in golang

plugins/proxy/proxy.go

@@ -0,0 +1,21 @@
+package proxy
+
+import (
+	common "github.com/dokku/dokku/plugins/common"
+	config "github.com/dokku/dokku/plugins/config"
+)
+
+// IsAppProxyEnabled returns true if proxy is enabled; otherwise return false
+func IsAppProxyEnabled(appName string) bool {
+	err := common.VerifyAppName(appName)
+	if err != nil {
+		common.LogFail(err.Error())
+	}
+
+	proxyEnabled := true
+	disableProxy := config.GetWithDefault(appName, "DOKKU_DISABLE_PROXY", "")
+	if disableProxy != "" {
+		proxyEnabled = false
+	}
+	return proxyEnabled
+}