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
Add two attributes for cinder volume

Add 'encrypted' and 'attachments' attributes for cinder
volume resource.

Change-Id: I920f97d196e5f4bed7bc8186b7d12157ee25edea
Merge "Add two attributes for cinder volume"
Merge "doc: Improve use of the support_status attribute"