Update .gitlab-ci.yml to support new settings

- list env vars
- also update manage.py and wsgi.py to use associated settings
4 jobs for 107-split-settings in 1 minute and 3 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Test
passed #2319
Go-py2.7

00:00:57

passed #2320
Go-py3.4

00:01:00

passed #2321
Go-py3.5

00:01:00

passed #2322
Go-py3.6

00:01:02

72.0%