This commit adds a new tox target to build PDF documentation.
It's a community goal[0] to have PDF docs available.
Also some minor fixes are needed for PDF:
- Only show genindex and search for HTML. Theses elements do not make
sense within PDF documents
- Do not include full config sample files. This will not work and
produces a "Dimension too large" error during the latex run.
[0]
https://governance.openstack.org/tc/goals/selected/train/pdf-doc-generation.html
Change-Id: I66b8c47d599c97e66c2ca76faa66204d5e7c9c3b
b1713e6255