js: we don't use the filesaver (!) and fastcdn is dead

So let's remove it.
Inclusion of FileSaver was a bad leftover from a code extraction.

rework_ui/rui_templates/rui_home.html

@@ -3,7 +3,6 @@
 {% block body %}
 <script src="https://code.jquery.com/jquery-2.2.4.min.js"></script>
 <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
-<script src="https://fastcdn.org/FileSaver.js/1.1.20151003/FileSaver.min.js"></script>
 
 <div id="filter" style="float: right">
   {{ domain_filter | safe }}