Remove the mongo driver (#3099)

* kills mongo

* changelog

* more refeences to mongo needed to go

.travis.yml

@@ -27,10 +27,6 @@ jobs:
         postgresql: "10"
       before_script:
         - psql -c 'create database red_db;' -U postgres
-    - env: TOXENV=mongo
-      services: mongodb
-      before_script:
-        - mongo red_db --eval 'db.createUser({user:"red",pwd:"red",roles:["readWrite"]});'
     # These jobs only occur on tag creation if the prior ones succeed
     - stage: PyPi Deployment
       if: tag IS present