The administration CSS is a mess, largely due to needing to work around

much of Django's own admin CSS rules to get things to look how we want.

This is going to be required for Django 1.11 support, as our CSS just

doesn't work with what they now have.
As a first step to cleaning this all up, this change splits up the admin

LessCSS files, helping us stay more organized. This will make it easier

to determine which styles are specific to certain components or pages of

the admin UI.
Right now, the styles built to override the Django Admin UI live in a

django.less file. The goal is to create a new file containing a more

manageable base set of styles, and to eventually remove or reduce the

rules in django.less.
This change also does not modify any styles or change them to use the

new naming scheme.

Tested all affected pages in the admin UI.