SQL performance improvements (#6378)

* Change queryStruct to use tx.Get instead of queryFunc

Using queryFunc meant that the performance logging was inaccurate due to the query actually being executed during the call to Scan.

* Only add join args if join was added

* Omit joins that are only used for sorting when skipping sorting

Should provide some marginal improvement on systems with a lot of items.

* Make all calls to the database pass context.

This means that long queries can be cancelled by navigating to another page. Previously the query would continue to run, impacting on future queries.

pkg/sqlite/image.go

@@ -965,10 +965,12 @@ func (qb *ImageStore) setImageSortAndPagination(q *queryBuilder, findFilter *mod
 		addFilesJoin := func() {
 			q.addJoins(
 				join{
+					sort:     true,
 					table:    imagesFilesTable,
 					onClause: "images_files.image_id = images.id",
 				},
 				join{
+					sort:     true,
 					table:    fileTable,
 					onClause: "images_files.file_id = files.id",
 				},
@@ -977,6 +979,7 @@ func (qb *ImageStore) setImageSortAndPagination(q *queryBuilder, findFilter *mod
 
 		addFolderJoin := func() {
 			q.addJoins(join{
+				sort:     true,
 				table:    folderTable,
 				onClause: "files.parent_folder_id = folders.id",
 			})