Add information about the release in which a resource has been added

[Gauvain Pocentek]

Currently there is no way to know in which OpenStack release a resource has been added when using the template_guide documentation.

An 'available_since' attribute could be added to resources to help the users know if they can use it on their OpenStack cloud.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/116443

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/116443
Committed: https://git.openstack.org/cgit/openstack/heat/commit/?id=0a99bf8fc3a7c17fd6bd3acf8b54a6bd550c4b08
Submitter: Jenkins
Branch: master

commit 0a99bf8fc3a7c17fd6bd3acf8b54a6bd550c4b08
Author: Gauvain Pocentek <email address hidden>
Date: Thu Sep 4 15:01:28 2014 +0200

    doc: Improve use of the support_status attribute

    This patch adds admonitions to the template_guide to indicate support
    status of resources to the reader. Deprecated resources will be clearly
    indicated, as well as the version in which a resource appeared.

    This patch also rework the generated markup to use paragraph nodes
    instead of inline nodes inside notes.

    Closes-Bug: #1360561
    Change-Id: I5ee9fd47f0aa9627beb842dc46aa3bac10060e13

[Thierry Carrez (ttx)]

Please keep bugs FixCommitted until published in a milestone release