Add selection actions bar.

src/app/task-lists/task-lists.component.html

@@ -19,8 +19,9 @@
       <mat-icon *ngIf="isSelectionModeEnabled() && isSelected(taskList)" class="selection-icon">done</mat-icon>
     </div>
     {{taskList.name}}
-    <ng-container >
-      SELECTED
-    </ng-container>
   </div>
 </div>
+<div class="selection-actions" *ngIf="isSelectionModeEnabled()">
+  <button class="raised">Renommer</button>
+  <button class="raised alert">Supprimer</button>
+</div>