Alerting: Export and provisioning rules into subfolders (#77450)

* Folders: Optionally include fullpath in service responses
* Alerting: Export folder fullpath instead of title
* Escape separator in folder title
* Add support for provisiong alret rules into subfolders
* Use FolderService for creating folders during provisioning
* Export WithFullpath() folder service function

---------

Co-authored-by: Tania B <yalyna.ts@gmail.com>
Co-authored-by: Yuri Tseretyan <yuriy.tseretyan@grafana.com>

pkg/services/folder/folderimpl/folder.go

@@ -34,6 +34,8 @@ import (
 	"github.com/grafana/grafana/pkg/util"
 )
 
+const FULLPATH_SEPARATOR = "/"
+
 type Service struct {
 	store                store
 	db                   db.DB
@@ -1109,6 +1111,36 @@ func (s *Service) buildSaveDashboardCommand(ctx context.Context, dto *dashboards
 	return cmd, nil
 }
 
+// SplitFullpath splits a string into an array of strings using the FULLPATH_SEPARATOR as the delimiter.
+// It handles escape characters by appending the separator and the new string if the current string ends with an escape character.
+// The resulting array does not contain empty strings.
+func SplitFullpath(s string) []string {
+	splitStrings := strings.Split(s, FULLPATH_SEPARATOR)
+
+	result := make([]string, 0)
+	current := ""
+
+	for _, str := range splitStrings {
+		if strings.HasSuffix(current, "\\") {
+			// If the current string ends with an escape character, append the separator and the new string
+			current = current[:len(current)-1] + FULLPATH_SEPARATOR + str
+		} else {
+			// If the current string does not end with an escape character, append the current string to the result and start a new current string
+			if current != "" {
+				result = append(result, current)
+			}
+			current = str
+		}
+	}
+
+	// Append the last string to the result
+	if current != "" {
+		result = append(result, current)
+	}
+
+	return result
+}
+
 // getGuardianForSavePermissionCheck returns the guardian to be used for checking permission of dashboard
 // It replaces deleted Dashboard.GetDashboardIdForSavePermissionCheck()
 func getGuardianForSavePermissionCheck(ctx context.Context, d *dashboards.Dashboard, user identity.Requester) (guardian.DashboardGuardian, error) {