support custom column selection for search result overview

the current set of shown information for search results is fixed and can not be customized by the user, but for different people different information is relevant.

onionoo provides a lot of information, would be great if search results were more customizable via the URL

examples:

first_seen
last_restarted
tor version / os
hostnames
as_name
*_bandwidth
*_probability
hide specific currently shown columns

torstatus allows for custom column selection, see: http://torstatus.blutmagie.de/column_set.php

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information