feature/person exodus

[thatbudakguy]

This PR addresses #186 and #253, but not #267 (the person list pages). It's a big one!

Some things to note:

• Multiple migrations that un-proxy the old Person model and make it independent from django's User
• Most properties of Profile move to the new Person (office location, phone, job title, etc.)
• Profile becomes a new wagtail Page model called ProfilePage (but the old Profile still exists, so it can be exodized)
• The admin section for this app is redone so that ProfilePages are managed through a special menu (similar to the current admin) and don't clutter the wagtail page tree - check out wagtail_hooks.py
• Some fancy Wagtail admin features are added, such as automatic export of people to excel/csv and inline editing of Titles on people
• A special PeopleLandingPage is created so that correct page hierarchy can be enforced through code
• I adopted a new convention (criticism welcome) of moving model-related tests for wagtail Page models to a file called test_pages.py for each app, so that test_models.py was less crowded and could focus on non-Page models.
• I tried to reduce this app's reliance on a single large fixture, which led to rewriting many tests and a lot of repetition of set-up code. This could be refactored later.

[codecov-io]

Codecov Report

Merging #268 (771a70d) into develop (8d7c85b) will decrease coverage by 10.03%.
The diff coverage is 95.49%.

@@             Coverage Diff              @@
##           develop     #268       +/-   ##
============================================
- Coverage    97.68%   87.64%   -10.04%     
============================================
  Files           99      125       +26     
  Lines         3150     3124       -26     
============================================
- Hits          3077     2738      -339     
- Misses          73      386      +313     

[rlskoeser]

Ok. I think I have looked at all the files (what a monster of a PR). Haven't run anything locally yet, there may be a few more things I need to look at when I do.

Happy with your decision to split out unit tests more, they needed to be broken out more.

[rlskoeser]

Updates since my last review look good; just one comment on some lines that I think are inside a for loop and shouldn't be.