This cleans up most of the warnings from sphinx (broken :doc: links,
broxygen role misuses, etc.). The remaining ones should be harmless,
but not quick to silence.
I found that the README for each component was a copy from the actual
repo, so I turned those in to symlinks so they don't get out of date.
- Added the known-devices log, and the script to log DHCP hostname per MAC address,
- Added DPD sig,
- Removed some scripts following a discussion with Seth.