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

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

pkg/services/folder/folderimpl/dashboard_folder_store.go

@@ -98,6 +98,8 @@ func (d *DashboardFolderStoreImpl) GetFolderByUID(ctx context.Context, orgID int
 	return dashboards.FromDashboard(&dashboard), nil
 }
 
+// GetFolders returns all folders for the given orgID and UIDs.
+// If no UIDs are provided then all folders for the org are returned.
 func (d *DashboardFolderStoreImpl) GetFolders(ctx context.Context, orgID int64, uids []string) (map[string]*folder.Folder, error) {
 	m := make(map[string]*folder.Folder, len(uids))
 	if len(uids) == 0 {