Photo upload loading/failure handling

[neilsarkar]

• provide atomic reducer actions to avoid overwriting photos
• delegate to actions/request instead of services/api, this will (theoretically) allow us to do retries
• refactor to remove maintenance of Quiz.js component state in favor of delegating to redux state

[neilsarkar]

tested with server 500'ing on image upload and with a 50 second delay.

[benjaminben]

This is cool, I wonder if we can recycle anything for the SettingsEditorPhotos component since I copypasta'd the update/destroy methods from there