proof: remove deprecated PQ2 module

man/man1/pq2-ana-dist.1

man/man1/pq2-cache.1

man/man1/pq2-info-server.1

man/man1/pq2-ls-files-server.1

man/man1/pq2-ls-files.1

man/man1/pq2-ls.1

man/man1/pq2-put.1

man/man1/pq2-redistribute.1

man/man1/pq2-rm.1

man/man1/pq2-verify.1

man/man1/pq2.1

man/man1/setup-pq2.1

proof/CMakeLists.txt

proof/pq2/CMakeLists.txt

proof/pq2/src/pq2actions.cxx

proof/pq2/src/pq2actions.h

proof/pq2/src/pq2main.cxx

proof/pq2/src/pq2ping.cxx

proof/pq2/src/pq2ping.h

proof/pq2/src/pq2wrappers.cxx