mw-tools-releng-tox-doc-publish

Run tox -edoc, and copy the generated html dir on Jenkins master which
happens to also be the document website.

Generates doc to:
 https://doc.wikimedia.org/mw-tools-releng/html/

Change-Id: I60cca6185f304b909aeef17c58d233f7f3c5f277