Normalize whitespace in source files

Ensure that no source files have trailing whitespace at end of lines and ensure that all files end with a single trailing newline.

This also adds Github Actions to enforce whitespace conventions.

src-ui/src/app/services/rest/saved-view.service.ts

@@ -44,7 +44,7 @@ export class SavedViewService extends AbstractPaperlessService<PaperlessSavedVie
       tap(() => this.reload())
     )
   }
-  
+
   patchMany(objects: PaperlessSavedView[]): Observable<PaperlessSavedView[]> {
     return combineLatest(objects.map(o => super.patch(o))).pipe(
       tap(() => this.reload())