Kh navbar

@boonrs Re-added a new navbar that makes more sense in with the redesign. Currently the Nav is hidden on mobile. I plan on making a responsive navbar in a separate branch.

Side-note: You'll notice I'm moving away from Bootstrap. The reason is, we only use a handful Bootstrap classes with the redesign. We might be able to reduce a lot of cruft in the code (+ load time etc) if we drop it entirely.