Ref T4222.
- Removes the old map and changes the CelerityResourceMap API to be entirely driven by the new map.
- The new map is about 50% smaller and organized more sensibly.
- This removes the /pkg/ URI component. All resources are now required to have unique names, so we can tell if a resource is a package or not by looking at the name.
- Removes some junky old APIs.
- Cleans up some other APIs.
- Added some feedback for bin/celerity map.
- CelerityResourceMap is still a singleton which is inextricably bound to the Phabricator map; this will change in the future.