QoS API and DB models

* Implements a vendor neutral database model centered around a QoS
object.
	* QoS objects have a type
		* Type is an Enum, with two current choices: "DSCP" for
		marking packets with a DSCP mark, and "ratelimit" which will
		throttle a port or all ports attached to a network based on a bandwidth value
	* QoS objects have policy key-value pairs for implementation specific behaviors

* QoS objects can be linked to Networks or Ports

* QoS mappings to a port overrides a network policy. If no policy is
specified, the policy for a port is inherited from the network.

Blueprint quantum-qos-api-db

Change-Id: Ia4d5c6cae82c579928129d0728cb03091d2869a7
Quality of Service API extension - RPC & Driver support

Change-Id: I1a259aac25377d80a3b0b87547be270b43bb1af8
Ml2 QoS API extension support

Implements blueprint ml2-qos

Change-Id: I9316632fbc9080d77fe5faa52d3f00c7cb78c134
Fix SQLAlchemy query

Change-Id: Ia755276a4492bd81de4e27777469f5d45e22cba6
Fix logic for updates

Change-Id: I3af384f00a72cd045ae66b546296d0f66f218115
Rename RPC method get_qos_for_network to get_qos_by_network

Change-Id: Ib1983ccf84eab777040a57b07e094ddb2702f1ba
Improve fallback flow creation for network qos

When there is no segmentation_id

Change-Id: I5836b22e3e77813c628d35086669c6ae05960226
Ensure network_id is in the vlan mappings

Change-Id: Id5f09e9dc55212c7a4350335d5fcb792f0388ba3
Documentation fix

Change-Id: Ifd6f28ba9e3cf9fefb50a54ff2d27f625c8dd68b
Another doc fix

Change-Id: I341f9f48da2bc823fbc5ceab295ce48d820d531a
Fix typo in get_qos_by_network unit test in QoSServerRpcApiTestCase

Change-Id: If47520a699207767824ade8f4a44a09f756239f8
Unit tests for QoSAgentRpcMixin

Change-Id: I650f59c994d0152dcea87bfdb29fd5440ab4946d
Complete migration from Mox to Mock

Change-Id: I215286739832eeac18b8d3966528e09ca5093920
Feedback from community

Change-Id: I72e1f0efbc0429e12849f44aa6b87786471783b4
Fix for DE32965 - QoS is not applied to a port

Pass in the integration bridge, so that OpenFlow statements for
ports are created using the correct bridge.

Change-Id: Ib4cb47022a9808414dfe9d264879529b5c083bd4
Co-Authored-By: Anthony Veiga <Anthony_Veiga@cable.comcast.com>