OR-834 Use Mongoose mock from helpers.mock where necessary
OR-834 new collaboration module

This will handle the collaboration stuff, other modules (i.e. community) will
handle the specific business code and proxy to this one
OR-834 Let modules declare their mongoose models before database connection

This ensures that the mongoose.connect call will be launched after the
modules "lib" state is achieved.
OR-834 Add a filesystem module loader in /modules
OR-834 Add registration facilities for collaboration derived models

Those methods can be consumed by third party modules to declare a new collaboration model
OR-834 add some tests for the collaboration query() method
OR-834 New linagora.esn.project module

This module contains the Mongoose Project schema / model creation
OR-834 Add project module in the list of ESN modules to start
Merge pull request #603 in OR/rse from ~MBAILLY/rse:OR-834-create-a-project-model to master

* commit '8bc772277b7797fc1084824374b3d1c5a45ae274':
  OR-834 Add project module in the list of ESN modules to start
  OR-834 New linagora.esn.project module
  OR-834 add some tests for the collaboration query() method
  OR-834 Add registration facilities for collaboration derived models
  OR-834 Add a filesystem module loader in /modules
  OR-834 Let modules declare their mongoose models before database connection
  OR-834 new collaboration module
  OR-834 Use Mongoose mock from helpers.mock where necessary