Subscription Confirmation Support-1

[OpenStack Infra]

https://review.openstack.org/316601
Dear bug triager. This bug was created since a commit was marked with DOCIMPACT.
Your project "openstack/zaqar" is set up so that we directly report the documentation bugs against it. If this needs changing, the docimpact-group option needs to be added for the project. You can ask the OpenStack infra team (#openstack-infra on freenode) for help if you need to.

commit 69c799734bcd0d1a0e85096f687f17ee3d0743c0
Author: wangxiyuan <email address hidden>
Date: Mon May 16 15:07:55 2016 +0800

    Subscription Confirmation Support-1

    The subscription confirmation feature will contain four patches:
    1. webhook with mongoDB
    2. email with mongoDB
    3. webhook with redis
    4. email with redis

    This patch is the first part of subscription confirmation feature for
    webhook with MongoDB. Others will be achieved in follow patches.

    This patch did:
    1. Add v2/queue/<queue_name>/subscription/<subscription_id>/confirm
    endpoint.
    2. Add a new config option: "require_confirmation".
    3. Add a new property "confirmed" to subscription resource for
    MongoDB driver.
    4. Add a new policy "subscription: confirm".
    5. Add a new property "message type" for notification.
    6. Use the pre-signed url in confirm request.
    8. Re-use POST subscription to allow re-confirm.
    9. Update notification for webhook subscription with mongoDB.
    10. Support unsubscrib the subscription
    11. Add tests for the feature.
    12. Add doc and sample.
    Docimpact
    APIimpact

    Change-Id: Id38d4a5b4f9303b12e22e2b5c248facda4c00143
    Implements: blueprint subscription-confirmation-support