Das mongodb separation (please review)

* on every startup first we run  check staging dir if it needs to be updated
* only after this the DAS server is started
* as a result, no cron jobs needed anymore, DAS would start immediately as DB will be ready before it is started minimizing the downtime, and we will be able to suppress some of the messy checks in the DAS code.

new changes are in this commit: 20eb3efd7c5dde208df057f893ca83abc85df8cc

TODOs/Might-dos:
- we might output different status if: waiting for MongoDB/updating databas vs DAS server is started