Chore: Remove ctlcmd and leftover envvar (#5392)

https://github.com/v2fly/v2ray-core/issues/360

common/platform/platform.go

@@ -8,10 +8,8 @@ import (
 )
 
 const (
-	PluginLocation  = "xray.location.plugin"
 	ConfigLocation  = "xray.location.config"
 	ConfdirLocation = "xray.location.confdir"
-	ToolLocation    = "xray.location.tool"
 	AssetLocation   = "xray.location.asset"
 	CertLocation    = "xray.location.cert"
 
@@ -79,17 +77,6 @@ func getExecutableDir() string {
 	return filepath.Dir(exec)
 }
 
-func getExecutableSubDir(dir string) func() string {
-	return func() string {
-		return filepath.Join(getExecutableDir(), dir)
-	}
-}
-
-func GetPluginDirectory() string {
-	pluginDir := NewEnvFlag(PluginLocation).GetValue(getExecutableSubDir("plugins"))
-	return pluginDir
-}
-
 func GetConfigurationPath() string {
 	configPath := NewEnvFlag(ConfigLocation).GetValue(getExecutableDir)
 	return filepath.Join(configPath, "config.json")