T219 searches view

Note that to use this view, you must set a value for STAFF_TOKEN in local_settings.py , and the URL to access the view would be /searches?token=<the 'secret' value for STAFF_TOKEN>

Also note:  This introduces a dependency on a css from django_tables2.  With DEBUG=True, runserver will find the css.  However, DEBUG=False will require settings for static files etc.  That would be a good reason not to merge this pull request just yet (but I wanted it to get an initial look).

It's pretty non-fancy but it works.  Might be nice to be able to click on a link and download a csv with the search data (but let's make that a separate issue, if agreed to)