Add toggle button to show/hide subtasks in task list view

app/Template/subtask/timer.php

@@ -0,0 +1,13 @@
+<span class="subtask-time-tracking">
+    <?php if (! empty($subtask['time_spent'])): ?>
+        <strong><?= $this->text->e($subtask['time_spent']).'h' ?></strong> <?= t('spent') ?>
+    <?php endif ?>
+
+    <?php if (! empty($subtask['time_estimated'])): ?>
+        <strong><?= $this->text->e($subtask['time_estimated']).'h' ?></strong> <?= t('estimated') ?>
+    <?php endif ?>
+
+    <?php if ($this->user->hasProjectAccess('SubtaskController', 'edit', $task['project_id']) && $subtask['user_id'] == $this->user->getId()): ?>
+        <?= $this->subtask->renderTimer($task, $subtask) ?>
+    <?php endif ?>
+</span>