file (discover): new discovery page: the discovery page will show service, own devices and roster contact devices offering file sharing. An extra field allow to enter free jid. Added a small message in photo/discover.html has photo album discovery is not yes implemented. New block and images macros.

{% extends 'base/base.html' %}
{% import 'input/xmlui.html' as xmlui with context %}

{% block body %}
<div id="tickets">
    {% for ticket in tickets %}
        <div class="ticket_full">
            {{ xmlui.generate(ticket) }}
        </div>
    {% endfor %}
</div>
{% endblock body %}