* Add a new configuration page and move content out from TP-Link. The
Configuration section in TP-Link is duplicating what is already in
config.toml.example, and given that we have recently added a lot of
new options I don't want to maintain multiple copies.
* Lots of anchor links were broken since we moved docs from README into
mdbook. Fix them all.
* Document that the key input feature is disabled since 0.4.0.
* Smaller cosmetic changes:
* Make TP-Link M7350 page consistent with TP-Link M7310 page.
* Fix indentation on some bullet points.
* Center-align the rayhunter logo in introduction.md to calm my soul.
It is still misaligned with the page title above itself.
* Add "edit on github" link in mdbook settings.
