first commit

application/views/components/timezone_dropdown.php

@@ -0,0 +1,18 @@
+<?php
+/**
+ * Local variables.
+ *
+ * @var string $attributes
+ * @var array $grouped_timezones
+ */
+?>
+
+<select <?= $attributes ?>>
+    <?php foreach ($grouped_timezones as $continent => $entries): ?>
+        <optgroup label="<?= $continent ?>">
+            <?php foreach ($entries as $value => $name): ?>
+                <option value="<?= $value ?>"><?= $name ?></option>
+            <?php endforeach; ?>
+        </optgroup>
+    <?php endforeach; ?>
+</select>