Move all redirect rule directories to an ids/ subdirectory.

[davidlehn]

Problem

• In hindsight, it would have been better to put all the redirect rules in a subdirectory.
  • Currently when visiting the project page you get a long load time and poor experience of documentation being a thousand page downs away.
  • It's difficult to have non-rule project files in the main repo.
• There are lots of redirect maintainers with various skill levels. Will this cause mass chaos? Or will everyone easily adapt?

Proposal

• I propose moving all rules, index.html, and other required served files to an ids/ subdirectory.
• To avoid making operational concerns too complex this will likely involve a very brief downtime to adjust server side paths.

[davidlehn]

#3264 might be too difficult to load, so maybe discuss here. The number of ids is stressing the initial simple design of this system.