Tools to convert Permatrac Wiki to Markdown format.

This is just the tool set for the Wiki, there's another set of scripts
for converting Trac tickets but I haven't yet converted them from the
task-specific form they're in at the moment (from an old Trac site
whose tickets I had to migrate to GitHub issues about five years
ago...).

As a test, we run the Markdown from the conversion process through
Pelican to generate a static site.  This may or may not be useful in
its own right, but for our purposes simply running the Pelican site
generator is helpful, since it spots a lot of dumb Markdown errors for
us (missing links, horribly borked Markdown syntax, etc).

Pelican content format: https://docs.getpelican.com/en/latest/content.html