reference page to new configuration system. Big update to administrator's
guide, chapters Runtime environment, Client authentication, and User
management, the latter two were part of the old Security chapter.
Add reference pages for utilities and remove standalone chapters for same.
Add material for an appendix on date/time properties, but not yet
integrated with the User's Guide.
Break up the former chapter on pg_options
into Admin and Programmer's Guides.
Split introduction sections into separate files to allow the legal notice
and notation sections appear in all documents without having the history
show up everplace too.
Add full list of reserved and non-reserved key words in syntax.sgml.
Add a separate chapter to the admin guide on security.
