Easing into history tracking: doc and app.conf stub.

[yelto]

The new tracking features get top billing in the release notes, it's one of the highlights of 2.0, but maybe the path to first use could be eased a little bit:

• The pointer to the manuals now point to docs.collectiveaccess.org. Assuming that
  https://manual.collectiveaccess.org/providence/user/workflow/location.html
  (which does refer to 1.8) remains valid, could it just be migrated to the new doc tree?

• That doc refers to additions/changes that have to be made in app.conf, so shouldn't a stub/skeleton/commented out example section be placed in that file as a reminder and a marker for admins to configure (or not) the new policies? In fact there is a mention in the heading of the Features section, but I don't see anything else, maybe it's an oversight?

On a very tenuously related very minor note, in line 2252 in app.conf
(a template which includes the only other mentions to tracking), "(inactive)" is not localizable.