ES6ify the code base

[cristeahub]

The code base (especially the backend) hasn't been updated to es6 yet.

Update the following to es6:

• Frontend
• Backend

[stianjensen]

Frontend has started the migration slowly. Controllers have been updated to ES6 class syntax etc.

[stianjensen]

For dasBoot, we will probably want to hold off on updating and consider the performance impact of updating syntax.

[cristeahub]

performance impact of updating syntax.

Is there a big impact there?

[stianjensen]

Depends.

https://kpdecker.github.io/six-speed/