feat(avatars): profile images

Getting there! Feel free to start looking @shane-tomlinson @pdehaan.

Still needs:
- [ ] profile-server client
- [ ] progress indicator screen
- [ ] unit tests for camera view
- [ ] unit tests for cropper widget
- [x] circular overlay on cropper
- [ ] functional tests
Your Cropper is a Decorator, so if we're were going to follow that philosophy, we would have method names that mimic the underlying component. `getImageData` sounds a bit like a getter, but it actually has a side effect of drawing the image. If you always want to couple those two operations, I'd rename tthis to `getImageDataAndDrawImage`. Otherwise, if we mimic the underlying method names, you'd have two methods, `drawImage` and `getImageData`