Break the UI down into components

Currently, the JS controllers and services are bloated and leaking responsibilities. Our two layers (controllers and services) are not well isolated and do not provide the sort of single-responsibility abstraction they should. It would do us much better to step by step break the services and views into components which define their own isolated models and behaviours.

This requires:
* extracting components from the XML views (i.e., reusable fragments)
* isolating the models bound to these components (i.e., not a shared global model)
* encapsulating the logic associated with these components into their own JS classes
* using the controllers to create this component dependency tree and delegate to it