base: implemented language button: - `component.menu` can now be used with a `{% call %}`, allowing extra HTML to be added after in the <nav> element - a language dropdown is shown if more than one translation is available, allowing to change page locale - if javascript is available, only the dropdown is visible, and changing it reload the page with new locale - if javascript is not available, a submit button is display to change the locale

{% import 'components/menu_labels.html' as ml %}

{% macro menu(menus, class='') %}
    <nav class="menu {{class}}">
        <ul>
        {% for name,url in menus %}
            <li><a class="menu_item menu_item--{{name}}" {{ {'href': url}|xmlattr }}>{{ml.label[name]}}</a></li>
        {% endfor %}
        </ul>
        {% if caller is defined %}
            {{ caller()}}
        {% endif %}
    </nav>
{% endmacro %}