RFC: moving SMM, PSD, and USD papers into share/doc/papers

[Ulrich Spörlein]

Hoi,

There are only a handful places in our tree, where these papers are next
to the sources they describe. All of them get build from
share/doc/papers, of course. There are two redundant Makefiles that are
unused and, sadly, one of the papers lives in contrib (nvi,
papers last touched >10 years ago).

Will anybody veto against me moving this stuff under share/doc/papers?

% find . -name \*.doc -type d
./lib/libc/rpc/PSD.doc
./bin/csh/USD.doc
./contrib/nvi/docs/USD.doc
./sbin/fsck_ffs/SMM.doc
./usr.sbin/config/SMM.doc
./usr.sbin/lpr/SMM.doc
./usr.sbin/timed/SMM.doc
./usr.bin/make/PSD.doc
./usr.bin/dc/USD.doc
./usr.bin/gprof/PSD.doc
./usr.bin/mail/USD.doc
./usr.bin/bc/USD.doc

Uli