Ported settings/apps logic to Ember.

Closes #2423

- Created the apps route to fetch apps from server
- Created controller for a single app
- Modified the template of the apps page to use this controller
- Created the Apps model
- Created AppAdapter to use the FixtureAdapter for Ember Data
Small nitpick; probably should either use `DS.attr()` or `DS.attr('string')` consistently, not both.