R1:d8c11a210605

Move build-time resources to "CelerityPhysicalResources" to fix Phame

Summary:
Ref T4222. This fixes some issues with Phame's resource construction.

Phame requires a fully virtual resource source, and since I want to run wordpress templates unmodified some day I don't want to build resource maps for skins.

Move all the stuff that depends on resource lists being discoverable at build time to `CelerityPhysicalResources`, and only generate maps for subclasses.

The root `CelerityResources` can now…