Implement #3332

I have intentionally split this up into separate commits, the first one is the actual change from Ruby to Node. Having the whole `_.template` function in Cakefile is not ideal (I cut it down though), but at least doesn't add another dependency. Better solutions welcome.

I've done this after three pints, so peer review would be highly welcomed.

Little note: Highlight.js parses object `keys` as `attribute`, so I deleted it from the `css` file to keep an equivalent style.

Second note: @michaelficarra the `run` expressions are javascript expressions, so we can't use `#{}`