Added docs to django app template

@wesleykendall @wilduck

I also moved coverage arguments in to `.coveragerc` and flake8 into `setup.cfg`

As a side note: I [upvoted and commented](https://bitbucket.org/ned/coveragepy/issue/304/attempt-to-get-configuration-from-setupcfg) on an issue for coverage to allow coverage configuration from `setup.cfg` so we can have a one stop shop for test configuration.