x11-wm/nscde: New port: modern and functional CDE

• Submitter becomes maintainer

sCDE is a retro but powerful UNIX desktop environment which resembles
CDE look (and partially feel) but with a more powerful and flexible
framework beneath-the-surface, more suited for 21st century unix-like
and Linux systems and user requirements than original CDE.

See also https://github.com/NsCDE/NsCDE

PR: 255929
Differential Revision: https://reviews.freebsd.org/D30591