Update swh-docs pipeline after documentation merge
All documentation parts have been merged in a single Sphinx instance, resulting in a single build tree. The pipeline for swh-docs still tries to publish 3 different build trees.
Staging instance, all changes can be removed at any time
All documentation parts have been merged in a single Sphinx instance, resulting in a single build tree. The pipeline for swh-docs still tries to publish 3 different build trees.