add monthly statistics page - #52

Closes #52 (closed) don't hesitate if you see anything wrong or missing.

smash/web/templates/statistics/breadcrumb.html

+<li><a href="{% url 'web.views.appointments' %}"><i class="fa fa-dashboard"></i> Dashboard</a></li>
+<li class="active"><a href="{% url 'web.views.statistics' %}">Statistics</a></li>
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