prelude section is prepared for general comments about a release [1].
At now neutron release notes use prelude section randomly.
Some rel notes use it and some do not.
This commit drop or move prelude section in Pike release notes.
In addition, some guideline on writing a release note
to the release notes howto page.
Change-Id: I53fefcc3eed30700d095c77d9e000319668097e8
reno includes release notes touched in a target release
even if they are added from past releases.
The recent release note cleanup I made as part of doc8 adoption
and some other cleanup touched release notes from past releases.
As a result, we see several number of release notes from past
release in the Pike release notes unexpectedly.
Also adds a warning note to the release notes howto page
Change-Id: I127f96896488e9992d9309d76055b4883f6a62f3
Closes-Bug: #1708560
* Update the URLs affected by the doc-migration
(/developer/<project>/ to <project>/latest/)
* Follow content rearrangement
* Convert links to local documents into :doc: or :ref:
* Use https instead of http for the updated links on docs.openstack.org.
Part of the doc-migration work.
Change-Id: I62e317d9198f175a43d73bbfd419b6878de90d5a