Update octavia-tempest-plugin configref

This patch updates the octavia-tempest-plugin configuration reference
documentation to only include octavia-tempest-plugin specific
configuration options.
This simplifies our documentation and means bugs in other plugins will
not break our configuration reference docs job.

It also re-enables the docs job, disabled in a previous patch.

Change-Id: I53d81ca7bd910838927d594bfb0e72320b9d1ec6
4 files changed