Fixes on DAU and MAU aggregations (#14418)

* Fixes on SAU and MAU aggregations

* Report new data from DAU/MAU

* Run tests agains a mongodb container in CI

* Try to run CI correctly

* Fix drop database

* Parse desktop app User Agent correctly

* Fix aggregation of past sessions

* Return past month today

* Fix bug

* Add migration

* Fixed migration

* Migration improvements

.circleci/config.yml

@@ -69,6 +69,7 @@ jobs:
     <<: *defaults
     docker:
       - image: circleci/node:8.11-stretch
+      - image: mongo:3.2
 
     steps:
       - checkout
@@ -129,7 +130,7 @@ jobs:
       - run:
           name: Unit Test
           command: |
-            meteor npm run testunit
+            MONGO_URL=mongodb://localhost:27017 meteor npm run testunit
 
       - restore_cache:
           keys: