Add MQ consumer, producer and payload base classes

Add MQ consumer, producer and payload base classes

Added MessagingProducer base class. A class implementing this base class
can send a cast message using the MQ service installed in the Yardstick
jumphost (RabbitMQ by default, other MQ could be implemented). The producer
will send messages to an specific topic.

Added MessagingConsumer base class. A class implementing this base class
will be able to receive any message sent by a MessagingPorducer class
publishing messages in the topic subscribed.

By default both Producer and Consumer "fanout" is True. That means every
Consumer will create a fanout Queue attached to the MQ Exchange topic. All
Consumers attached to this topic will receive the message sent by the
Producer [1].

Added Payload base class. To send data through the message queue service,
a Payload derived object should be created. This base class allows to
define the attributes container in the class, convert the object to a dict
and retrieve the object from a dict.

Added a new library, "oslo.messaging", to implement the RPC client and
server.

[1]http://blog.thedigitalcatonline.com/blog/2013/08/21/some-tips-about-amqp-direct-exchanges/

JIRA: YARDSTICK-1074

Change-Id: I63932b5fb3de2bdc1270fc83295630a2a349e2a6
Signed-off-by: Rodolfo Alonso Hernandez <rodolfo.alonso.hernandez@intel.com>