CDB-3629 Uses one request to redis to retrieve all connection params
Moves auth functionality to its own directory
New authentication mechanism: checks in advance if credentials are provided
in order to do a single request to redis to retrieve the required database
connection parameters.
Removes console.log
Fixes redis-mpool dependency
Using new method from cartodb-redis to retrieve oauth values so we
can reuse the same redis-mpool
Merge pull request #166 from CartoDB/CDB-3629

Handle credentials/authentication using less calls to redis