* tripleo-docs now passes sphinx-build -W test.
* Remove unneeded files.
* Don't mix toctree with includes to avoid duplicate labels.
* Add a common file for link references shared across docs.
* Make cross-references work across files.
* Move upload_single_image
Change-Id: I319e0d4e4dd03b7f769d9d38ad2829d6cc9a679a
Depends-On: I839a593df2116264112a6060f1f306910cfba197
77f5365c8a