Add delete task functionality (#72)

closes #62

Reviewed-on: #72

frontend/allowance-planner-v2/src/app/services/task.service.ts

@@ -30,4 +30,8 @@ export class TaskService {
     completeTask(id: number) {
         this.http.post(`${this.url}/task/${id}/complete`, {}).subscribe();
     }
+
+    deleteTask(id: number) {
+        this.http.delete(`${this.url}/task/${id}`).subscribe();
+    }
 }