A first update of subsurface V4.0 manual

This starts mostly from scratch. It removes big chunkgs of the old manual,
the old pictures and starts with new visuals and new descriptions. A lot
more work is needed, but it's a good start.

Signed-off-by: Willem Ferguson <willem@willem-Precision-M4700.(none)>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>