Allow CelerityResourceResponse to hold resources from multiple maps
Summary:
Ref T4222. Currently, CelerityResourceResponse holds response resources in flat maps. Instead, specify which map resources appear in.
Also, provide `requireResource()` and `initBehavior()` APIs on the Controller and View base classes. These provide a cleaner abstraction over `require_celerity_resource()` and `Javelin::initBehavior()`, but are otherwise the same. Move a few callsites over.
Test Plan:
- Reloaded pages.
- Browsed around Differential.
Reviewers: btrahan, hach-que
Reviewed By: btrahan
CC: aran
Maniphest Tasks: T4222
Differential Revision: https://secure.phabricator.com/D7876