Support file-less scenes. Add scene split, merge and reassign file (#3006)

* Reassign scene file functionality
* Implement scene create
* Add scene create UI
* Add sceneMerge backend support
* Add merge scene to UI
* Populate split create with scene details
* Add merge button to duplicate checker
* Handle file-less scenes in marker preview generate
* Make unique file name for file-less scene exports
* Add o-counter to scene update input
* Hide rescan for file-less scenes
* Generate heatmap if no speed set on file
* Fix count in scene/image queries

pkg/scene/query.go

@@ -16,6 +16,7 @@ type Queryer interface {
 
 type IDFinder interface {
 	Find(ctx context.Context, id int) (*models.Scene, error)
+	FindMany(ctx context.Context, ids []int) ([]*models.Scene, error)
 }
 
 // QueryOptions returns a SceneQueryOptions populated with the provided filters.