Add documentation datacube

Summary:
Directory created on WindRiver in April 2022 to build documentation
for Keruald OmniTools.

Old name was /datacube/doc, but that's confusing with docs.

Ref T2017

Test Plan: Deploy on WindRiver

Reviewers: dereckson

Reviewed By: dereckson

Maniphest Tasks: T2017

Differential Revision: https://devcentral.nasqueron.org/D3472