Apply model deduping by using Backbone.ModelFactory, fixes T101

Summary:
- use [[https://github.com/misteroneill/backbone-model-factory | ModelFactory]] for all models
- add backbone-model-factory using bower and include in App.js

Test Plan:
- `bower install`
- load web ui, login
- edit my profile
- nothing is broken, sidebar updates

Reviewers: eyedol, rjmackay

Reviewed By: rjmackay

Subscribers: PapaLee, lkamau, dkobia

Maniphest Tasks: T101

Differential Revision: https://phabricator.ushahidi.com/D133