This patch set adds a relative symlink from docs/source/releasenotes
to releasenotes/source/ so that releasenotes can be published
to deckhand.readthedocs.io. A new tab link is added on the
documentation page which references Deckhand's release notes.
The command used to generate the symlink was:
ln -rs releasenotes/source/ docs/source/releasenotes
Change-Id: I07058ca47ecc7b1fb211cae53aedc5f796542cff
d32c7a2c8d