We updated version of moment and moment-timezone as our current versions are outdated making Discourse Dates broken on places where timezone had updates, like here in Brazil.
This also update highlightJS to the latest version and corrected a test that relied on a no longer supported locale in
moment.
Moves Highlight.js files to vendor/assets/javascripts
Adds Highlight.js in yarn package management
Removes old rake task and reliance on NPM to build Highlight.js
Highlight.js is now integrated in the "javascript:update" rake task