engine: support for adding network qos for rest-api

* NetworkQoS will override QosBase
* Move NetworkQos dao to use QosBaseDao
* Move network_qos data to qos table, and all its references
* Move network qos CRUD command to use qos infra

Change-Id: I34f43f9edc10b7b52e096b2b6f1f43d19f129ed5
Bug-Url: https://bugzilla.redhat.com/1078863
Signed-off-by: Gilad Chaplik <gchaplik@redhat.com>
restapi: support for adding network QoS

Adding a NETWORK type for QoS entity, and adding it
to current QoS infra.

Adding QoS to Vnic Profile entity.

Change-Id: I5104c61b484683fbee0ead9a9d0934ec93a6c4cd
Bug-Url: https://bugzilla.redhat.com/1078863
Signed-off-by: Gilad Chaplik <gchaplik@redhat.com>
engine: set QoS href under profile

* Add a qurey to fetch all qos entities by type
* For disk, cpu and vnic profile, fetch all qos objects (if needed),
and set the DataCenter, inorder to map it to
correct path (/DataCenter/<dc_id>/qoss/<qos_id>/)

Change-Id: Ib345485d9d64d3adf28c2ea61a17c0cc0c828abb
Bug-Url: https://bugzilla.redhat.com/1078863
Signed-off-by: Gilad Chaplik <gchaplik@redhat.com>