New Font & Theme, keymap fixes & layout changes

BLUI will now load Roboto-Regular.ttf on startup, and that, combined with the new color theme make BLUI feel much more Unreal.
I hid a few headers and changed colors around to increase readability. There are two areas that share the same font, one with a dark background, the other a lighter background, so the theme ended up a little lighter overall than I would have liked, but you can always switch back to the Blender Dark theme without affecting the templates functioning in any way.