Move editnodetype page form logic to a backend Perl script.

       Note: new_node attributes have not yet been converted from
       names for osid's and imageid's to new-style integer indices.
     www/editnodetype.php3 - The reworked PHP page, including
       an EditNodeType function bridging to the script via XML.
     backend/{editnodetype,GNUmakefile}.in configure configure.in - New backend script,
       including wildcarding on %xmlfields table entries to handle dynamic attributes.
     sql/database-fill.sql - Add table_regex 'node_types' checking patterns.