Added configuration rules to set MongoLid connection parameters.

If bundle configuration was not present in app/config.yml file,
the default values of MongoDB will be used:
    - hostname: localhost
    - port: 27017
    - username: <null>
    - password: <null>

And MongoLid will connect to database 'mongolid' automatically.

If you want to override this settings, just follow this structure
in app/config.yml:

mongolid:
  connections:
    default:
      hostname: '192.168.0.1'
      port: 17027
      username: 'mongolid-username'
      password: 'ultra-mongo-secret'
      database: 'another_mongo_db'

You can overwrite only the parameters that you want, example:
mongolid:
  connections:
    default:
      username: 'mongo-user'
      password: 'mongo-pass'

Thus, MongoLid will connect to 'mongolid' database at on
localhost:27017 using 'mongo-user' and 'mongo-pass' credentials