Nested folders: Allow creating folders with duplicate names in different locations (#77076)

* Add API test

* Add move tests

* Fix create folder

* Fix move

* Fix test

* Drop and re-create index so that allows a folder to contain a dashboard and a subfolder with same name

* Get folder by title defaults to root folder and optionally fetches folder by provided parent folder

* Apply suggestions from code review

pkg/services/folder/model.go

@@ -13,6 +13,7 @@ import (
 var ErrMaximumDepthReached = errutil.BadRequest("folder.maximum-depth-reached", errutil.WithPublicMessage("Maximum nested folder depth reached"))
 var ErrBadRequest = errutil.BadRequest("folder.bad-request")
 var ErrDatabaseError = errutil.Internal("folder.database-error")
+var ErrConflict = errutil.Conflict("folder.conflict")
 var ErrInternal = errutil.Internal("folder.internal")
 var ErrCircularReference = errutil.BadRequest("folder.circular-reference", errutil.WithPublicMessage("Circular reference detected"))
 var ErrTargetRegistrySrvConflict = errutil.Internal("folder.target-registry-srv-conflict")
@@ -144,9 +145,10 @@ type DeleteFolderCommand struct {
 type GetFolderQuery struct {
 	UID *string
 	// Deprecated: use FolderUID instead
-	ID    *int64
-	Title *string
-	OrgID int64
+	ID        *int64
+	Title     *string
+	ParentUID *string
+	OrgID     int64
 
 	SignedInUser identity.Requester `json:"-"`
 }