Chore: Add WARN log if grafana server process is running with elevated privileges (#35205)

* warn on linux

* add warning for grpc plugins

* add windows support

* update go.mod

* reorganize imports

* update naming

* remove Windows logic

* simplify and add check for when UID and EUID don't match

* fix build

* tidy go.mod

* feedback

* cleanup + migrate

pkg/setting/setting.go

@@ -807,24 +807,6 @@ func NewCfgFromArgs(args CommandLineArgs) (*Cfg, error) {
 	return cfg, nil
 }
 
-var theCfg *Cfg
-
-// GetCfg gets the Cfg singleton.
-// XXX: This is only required for integration tests so that the configuration can be reset for each test,
-// as due to how the current DI framework functions, we can't create a new Cfg object every time (the services
-// constituting the DI graph, and referring to a Cfg instance, get created only once).
-func GetCfg() *Cfg {
-	if theCfg != nil {
-		return theCfg
-	}
-
-	theCfg, err := NewCfgFromArgs(CommandLineArgs{})
-	if err != nil {
-		panic(err)
-	}
-	return theCfg
-}
-
 func (cfg *Cfg) validateStaticRootPath() error {
 	if skipStaticRootValidation {
 		return nil