JS conversion

First part of converting Prototype code to jQuery or vanilla JS. I generally tried to use vanilla JS instead of jQuery for simple things like add/removing class tags, hiding/showing divs, etc, to remove the extra abstraction that creating jQuery objects comes with.

This includes changes/fixes from https://github.com/MarkUsProject/Markus/pull/1244 and https://github.com/MarkUsProject/Markus/pull/1247

Dashboard graphs are now rendered with Chart.js instead of Bluff.

Sorry about the massive number of files changed, I didn't realize I changed so many. :\