clear up useless env file

conf/config.go

@@ -1,21 +0,0 @@
-package conf
-
-import "sync"
-
-type Config struct {
-	PublicKeyPath    string
-	PrivateKeyPath   string
-	DHTEndpointPort  int64
-	PSKPath          string
-	BootstrapAddress string
-}
-
-var instance *Config
-var once sync.Once
-
-func GetConfig() *Config {
-	once.Do(func() {
-		instance = &Config{}
-	})
-	return instance
-}