Allow the HOMEDIR and ETCDIR to be configurable via Makefile ENV. Add FreeBSD user creation support.
usr/share/mercurial-server
usr/share/mercurial-server/init
usr/share/mercurial-server/mercurialserver
usr/share/doc/mercurial-server
etc/mercurial-server
etc/mercurial-server/remote-hgrc.d
etc/mercurial-server/keys
etc/mercurial-server/keys/root
etc/mercurial-server/keys/users