Changing base tones for dark and bright mode.

[lukasdiegelmann]

This is a request to switch from#000000 to a more friendly dark tone for the dark mode of monocircuit applications.

This was invoked by the perfect tone google has achieved in their products. For the normal bright mode #ffffff persists for now but will probably changed soon, too.

[lukasdiegelmann]

MaterialUI

This will be treated by materialui, they have put a lot of thought into this. It is actually by google, too.