Remove usages of and references to <input type="datetime">

It has been removed from the HTML specification: https://github.com/whatwg/html/issues/336
Only Presto Opera ever implemented a special UI for it.

[skip sauce]

docs/components/forms.md

@@ -114,7 +114,7 @@ Below is a complete list of the specific from controls supported by Bootstrap an
         Textual inputs
       </td>
       <td>
-        {% markdown %}`text`, `password`, `datetime`, `datetime-local`, `date`, `month`, `time`, `week`, `number`, `email`, `url`, `search`, `tel`, `color`{% endmarkdown %}
+        {% markdown %}`text`, `password`, `datetime-local`, `date`, `month`, `time`, `week`, `number`, `email`, `url`, `search`, `tel`, `color`{% endmarkdown %}
       </td>
     </tr>
     <tr>