Update our media send flow to allow users to send multiple images/videos
at once. This change includes:
- New in-app media picker flow.
- Ability to caption images and videos.
- Image editing tools are made more prominent in the flow.
- Some fixes to the image editing tools.
A new, fullscreen camera capture flow that easily allows you to capture
and edit a photo before sending it. Replaces the current half-screen
camera button.
