Optimize search3, by removing OFFSET when paginating (#2655)

* Optimize pagination, removing offset

* For search, don't add `where` clause for empty queries

* Revert "Replace `COUNT(DISTINCT primary_key)` with `COUNT(*)`"

Genres are required as part of the count queries, so filter by genres work

* Optimize search3 query, using order by id if it is a "" query.

Also fix the optimizePagination query logic

* Allow offset optimizer threshold to be configured

persistence/mediafile_repository.go

@@ -91,7 +91,7 @@ func (r *mediaFileRepository) Get(id string) (*model.MediaFile, error) {
 func (r *mediaFileRepository) GetAll(options ...model.QueryOptions) (model.MediaFiles, error) {
 	sq := r.selectMediaFile(options...)
 	res := model.MediaFiles{}
-	err := r.queryAll(sq, &res)
+	err := r.queryAll(sq, &res, options...)
 	if err != nil {
 		return nil, err
 	}