Add a count of elements to pagination elements (#219)

Also, add a second, upper pagination element to orders and attendees
list sites as those tend to get long.

src/pretix/control/templates/pretixcontrol/orders/index.html

@@ -57,6 +57,7 @@
             <button class="btn btn-primary" type="submit">{% trans "Filter" %}</button>
         </form>
         </p>
+        {% include "pretixcontrol/pagination.html" %}
         <div class="table-responsive">
             <table class="table table-condensed table-hover">
                 <thead>