VID-2009

- Not using JSSnippets for media gallery
- Using sloth to lazy load gallery initialization

This will need to be cherry-picked into dev. 

There's a lot of whitespace diffs so it's easier to read with https://github.com/Wikia/app/pull/4912/files?w=1. 
@hakubo, good catch. Was copied and pasted, but I'll fix it. And thanks for taking a look!