OPDS-PS v1.2 Support + a few bugfixes (#1869)

* Fixed up a localization lookup test case

* Refactored some webp to a unified method

* Cleaned up some code

* Expanded webp conversion for covers to all entities

* Code cleanup

* Prompt the user when they are about to delete multiple series via bulk actions

* Aligned Kavita to OPDS-PS 1.2.

* Fixed a bug where clearing metadata filter of series name didn't clear the actual field.

* Added some documentation

* Refactored how covert covers to webp works. Now we will handle all custom covers for all entities. Volumes and Series will not be touched but instead be updated via a RefreshCovers call. This will fix up the references much faster.

* Fixed up the OPDS-PS 1.2 attributes to only show on PS links

UI/Web/src/app/collections/_components/collection-detail/collection-detail.component.ts

@@ -103,7 +103,8 @@ export class CollectionDetailComponent implements OnInit, OnDestroy, AfterConten
         });
         break;
       case Action.Delete:
-        this.actionService.deleteMultipleSeries(selectedSeries, () => {
+        this.actionService.deleteMultipleSeries(selectedSeries, successful => {
+          if (!successful) return;
           this.bulkSelectionService.deselectAll();
           this.loadPage();
           this.cdRef.markForCheck();