R1:bcc5e55af288

Push construction of routing maps into Sites

Summary:
This enables CORGI.

Currently, `AphrontSite` subclasses can't really have their own routes. They can do this sort of hacky rewriting of paths, but that's a mess and not desirable in the long run.

Instead, let subclasses build their own routing maps. This will let CORP and ORG have their own routing maps.

I was able to get rid of the `PhameBlogResourcesSite` since it can really just share the standard resources site.

Test Plan:
- With no base URI…