Download Refactor (#483)

# Added
- New: Cards when processing a download shows a spinner for the progress of the download

# Changed
- Changed: Downloads now always take the backend filename and are streamed in a more optimal manner, reducing the javascript processing that was needed previously.
==================================

* Started refactor of downloader to be more UX friendly and much faster.

* Completed refactor of Volume download to use a new mechanism. Downloads are streamed over and filename used exclusively from header. Backend has additional DB calls to get the Series Name information to make filenames nice.

* download service has been updated so all download functions use new event based observable. Duplicates code for downloading, but much cleaner and faster.

* Small code cleanup

UI/Web/src/app/app.module.ts

@@ -25,6 +25,7 @@ import { ReviewSeriesModalComponent } from './_modals/review-series-modal/review
 import { CarouselModule } from './carousel/carousel.module';
 import { NgxSliderModule } from '@angular-slider/ngx-slider';
 
+
 import * as Sentry from '@sentry/angular';
 import { environment } from 'src/environments/environment';
 import { version } from 'package.json';
@@ -134,6 +135,7 @@ if (environment.production) {
       countDuplicates: true,
       autoDismiss: true
     }),
+    
   ],
   providers: [
     {provide: HTTP_INTERCEPTORS, useClass: ErrorInterceptor, multi: true},