Make metrics endpoint configurable

config/config.go

@@ -34,6 +34,7 @@ type HoneypotConfig struct {
 type FrontendConfig struct {
 	ListenAddr             string                 `toml:"ListenAddr"`
 	LogLevel               string                 `toml:"LogLevel"`
+	MetricsEnable          bool                   `toml:"MetricsEnable"`
 	AccessLogEnable        bool                   `toml:"AccessLogEnable"`
 	AccessLogIgnoreMetrics bool                   `toml:"AccessLogIgnoreMetrics"`
 	Autocert               FrontendAutocertConfig `toml:"Autocert"`