[mod] theme: improve thumbnails display on results page

Deletes thumbnails instead of showing an error image and also moves them to the right side. Also gives them a background and makes them into rounded 4:3 rectangles for better ui.

searx/templates/simple/result_templates/packages.html

@@ -70,6 +70,7 @@
     </div>
   {%- endif -%}
 </div>{{- '' -}}
+</div>
 <div class="break"></div>
 
 {{- result_footer(result) }}