Added the ability to download (export) archives from subscriptions

src/app/dialogs/subscription-info-dialog/subscription-info-dialog.component.html

@@ -21,5 +21,7 @@
 
 <mat-dialog-actions>
     <button mat-button mat-dialog-close>Close</button>
+    <button mat-stroked-button (click)="downloadArchive()" color="accent">Export Archive</button>
+    <span class="spacer"></span>
     <button mat-button (click)="unsubscribe()" color="warn">Unsubscribe</button>
 </mat-dialog-actions>

src/app/dialogs/subscription-info-dialog/subscription-info-dialog.component.scss

@@ -4,4 +4,6 @@
 
 .info-item-value {
     font-size: 13px;
-}
+}
+
+.spacer {flex: 1 1 auto;}

src/app/dialogs/subscription-info-dialog/subscription-info-dialog.component.ts

@@ -29,4 +29,11 @@ export class SubscriptionInfoDialogComponent implements OnInit {
     });
   }
 
+  downloadArchive() {
+    this.postsService.downloadArchive(this.sub).subscribe(res => {
+      const blob: Blob = res;
+      saveAs(blob, 'archive.txt');
+    });
+  }
+
 }