Show campaign info + last updated images + cta in Campaign: page

Currently it shows a rather useless JSON structure.

This patchset instead shows a parsed title, description, a CTA
asking the user to upload more, and a gallery of last ~24 images
that have been uploaded via this campaign in reverse chronological
order. Has contributors count + contributions count as well.

Change-Id: I9eb5949785ab17a0b07b8fda2588b3d9dcb88db8
Show anons a 'Create account to upload button'

Much better workflow for anons looking at the page than before.

Change-Id: Icdebf00f60f0039f3f56b0a598772868ab785aff
Style the 'view all uploads' link better

Change-Id: I273379ac9cb41f3640f4c5774ddf07a49f439a67
Merge changes I273379ac,Icdebf00f,I9eb59497

* changes:
  Style the 'view all uploads' link better
  Show anons a 'Create account to upload button'
  Show campaign info + last updated images + cta in Campaign: page