same naming scheme as that used by the doc/ repo.
Update docs.sgml to point to the documentation in this canonical location.
Update the FAQ/ and handbook/ directories to use symlinks to point to
the real documentation under doc/en_US.ISO_8859-1/. This means that local
testing of the site (and mirrors) will still work as expected using the
legacy URLs. Mirrors that expect to see a lot of traffic are advised to
alter their web server configuration so that $WEBROOT/FAQ and $WEBROOT/handbook
are redirected to $WEBROOT/doc/en_US.ISO_8859-1/books/{faq,handbook},
instead of relying on the symlinks.
Discussed on: doc, www
