fluxconf: remove package

The wm/fluxconf package has been dead upstream for over a decade, fails
to build with default pkgsrc settings in most environments (it has of
course continually bit-rotted), and is also actively harmful for users
in some contexts. It doesn't support the current config format that
Fluxbox 1.3 uses, so it will actually corrupt config files.

As discussed on pkgsrc-users:
http://mail-index.netbsd.org/pkgsrc-users/2020/01/14/msg030221.html


(gutteridge)