Add local table of contents to auto-generated configuration page

As a follow up of https://github.com/openmicroscopy/openmicroscopy/pull/3020 and https://github.com/openmicroscopy/ome-documentation/pull/984#issuecomment-55578326, this PR adds a local table of content to the auto-generated configuration properties page.

Additionally, the subheadings are converted to `^` for compliance with the documentation stylistic rules and `web_parser.py` is flake8'ed.

/cc @aleksandra-tarkowska @hflynn