Story 1904: Filters to reduce copyvios on mobile

Show a confirm dialog when image has no EXIF data.
Add browser tests too.

In the process, remove dynamic loading of upload modules from
PhotoUploaderButton.js (it's already in routes.js).

Change-Id: I38993dfde8f2689318961d4bf215164fce37d222
Merge "Story 1904: Filters to reduce copyvios on mobile"