Adds support for optional thumbnails into the standard fineuploader template.

What I did

• Added an optional thumbnail img to the standard fineuploader template.
  • Active only if you set a $thumb_size variable when loading the template.
  • As seen in the default Fineuploader template here: https://docs.fineuploader.com/quickstart/02-setting_options.html
• This change comes from, and is in place in Art Money; used when uploading user ID images.

Implications

None

Setup

None

How to test

• Code review. Should be sufficient?