Migration of Openstack Project is held in
*.rst files and build with Sphinx.
Following change provides:
* technical documention
* api guide
* api ref
* releasenotes
Note:
For now, generating codebase documentation is disabled.
It caused gate failures because of, yet unnown, reasons.
In order to pull this foundation, this part is skipped.
Extra:
* provided venvs descriptions to let user know what is the scope
Story: 2001058
Task: 4665
Change-Id: Ieb2b58e165de1617748d97d997af368bd91d5c0e