Write log entry on file removal

app/Template/event/task_file_destroy.php

@@ -0,0 +1,10 @@
+<p class="activity-title">
+    <?= e('%s removed a file from the task %s',
+            $this->text->e($author),
+            $this->url->link(t('#%d', $task['id']), 'TaskViewController', 'show', array('task_id' => $task['id'], 'project_id' => $task['project_id']))
+        ) ?>
+    <small class="activity-date"><?= $this->dt->datetime($date_creation) ?></small>
+</p>
+<div class="activity-description">
+    <p class="activity-task-title"><?= $this->text->e($file['name']) ?></p>
+</div>