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/infra/process/process.go

@@ -0,0 +1,5 @@
+package process
+
+func IsRunningWithElevatedPrivileges() (bool, error) {
+	return elevatedPrivilegesCheck()
+}

pkg/infra/process/root_check.go

@@ -0,0 +1,20 @@
+// +build !windows
+
+package process
+
+import (
+	"fmt"
+	"os"
+	"os/user"
+)
+
+func elevatedPrivilegesCheck() (bool, error) {
+	u, err := user.Current()
+	if err != nil {
+		return false, fmt.Errorf("could not get current OS user to detect process privileges")
+	}
+
+	return (u != nil && u.Username == "root") ||
+		os.Geteuid() != os.Getuid() ||
+		os.Geteuid() == 0, nil
+}

pkg/infra/process/root_check_windows.go

@@ -0,0 +1,8 @@
+// +build windows
+
+package process
+
+func elevatedPrivilegesCheck() (bool, error) {
+	// TODO implement Windows process root check
+	return false, nil
+}