Related to:
- https://review.opendev.org/#/c/723044/
- https://governance.openstack.org/tc/goals/selected/ussuri/project-ptl-and-contrib-docs.html

Change-Id: I00881701f401597972de9e02f1493a2746038be8

Replace the doc links with the lastest ones according to the OpenStack website.

Change-Id: Ic3054d1b55e330a91783754ef3338b927fae697e

Replace URLs for workflow documentation to appropriate parts of the
OpenStack Project Infrastructure Manual.

Change-Id: Iae073e56006cc04fb852cef0425cbade533e8cae

Point contributors to the correct launchpad page.

Change-Id: I4ce980a8957a186ec3e1b4be2e0ee3ecf333b849

Also add docs environment to tox.ini to simplify local docs generation

Change-Id: Ie0444264e4e02d206ded2c7568d58a26cfec3ae2