[Nested Folder] Delete folder methode (#58444)

* transfer DeleteFolder changes from larger PR

* finish some thingies

* add the simplest delete logics

* some intermedia steps

* fix tests

* add test

* fix some comments

Co-authored-by: yangkb09 <yangkb09@gmail.com>

pkg/services/folder/folderimpl/store_fake.go

@@ -12,6 +12,7 @@ type FakeStore struct {
 	ExpectedError   error
 
 	CreateCalled bool
+	DeleteCalled bool
 }
 
 func NewFakeStore() *FakeStore {
@@ -26,6 +27,7 @@ func (f *FakeStore) Create(ctx context.Context, cmd folder.CreateFolderCommand)
 }
 
 func (f *FakeStore) Delete(ctx context.Context, uid string, orgID int64) error {
+	f.DeleteCalled = true
 	return f.ExpectedError
 }