Implement Mitaka ODS Documentation structure

From this etherpad:
https://etherpad.openstack.org/p/kolla-mitaka-documentation

Lay groundwork for structure of new documentation layout.

Further work will finish the job on this doc work.

Note in a later change I793244c47ffbe0ba304e79bacf708494e59d99c4
ansible-deployment, deploy-all-in-one-node, and quickstart.rst
will be merged into one document.

Change-Id: I42b576ffab796da6e27adc9dbf55b2ceed641c16