Add doc8 a documentation style checking package

Many of the projects are starting to do style checks
on there specs files or other rst files so it seems
appropriate to use a small utility library to do these
kinds of checks (to avoid repeated copied code).

Doc8 starts to create a path for a common rst documentation
checking suite that can avoid the 'test_titles.py' tests
that are appearing in the various specification repositories.

Projects that currently can benefit from this package:

- TaskFlow
- Cinder
- Others with spec repos (nova, glance, oslo...)
 
Change-Id: Ie942497d88ad4dc9a4b3e58bea213354ec5513c5
Add nodeenv for horizon

nodeenv is a tool to create isolated node.js environments. It is already
used in the tuskar-ui project for testing, and would be introduced in
Horizon in patch https://review.openstack.org/#/c/97237/

It is Python 3 compatible and released under the BSD license.

Change-Id: I17d5e9ac36a7982b21e0fdf70d52f6be5069e850
Implements: blueprint node-toolchain
Merge "Add nodeenv for horizon"
Merge "Add doc8 a documentation style checking package"