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

{% extends 'base/base.html' %}

{% block body %}
<div class='invitation_header'>
    <h1>{% trans %}Welcome {{name}}{% endtrans %}</h1>
    <p class='instructions'>{% trans %}You have been invited to participate with the community, please choose an action below{% endtrans %}</p>
</div>

{% if include_url is defined %}
<iframe id='include_main' src='{{include_url}}'></iframe>
{% endif %}

{% endblock body %}