bugfix: web/.phpPgAdmin/.htaccess: only append subject if non-empty, to avoid confusing redirect.php

bugfix: web/.phpPgAdmin/.htaccess: custom pages: need to handle in query string because .php filename would be treated as path element

web/.phpPgAdmin/.htaccess: support custom .php pages

bugfix: web/.phpPgAdmin/.htaccess: work around phpPgAdmin bug that causes page to be ignored when not logged in

web/.phpPgAdmin/.htaccess: extract path components 1st->last: documented that can't use subject param for this because that goes to the last selected tab, not the default (leftmost) tab

web/.phpPgAdmin/.htaccess: support linking to a function

web/.phpPgAdmin/.htaccess: support linking to the functions list

web/.phpPgAdmin/.htaccess: support linking to a view

web/.phpPgAdmin/.htaccess: allow linking directly to the views list of a schema

web/.phpPgAdmin/.htaccess: refactored to build the URL incrementally, extracting path components 1st->last, instead of handling each # of path components as a separate case (which was more rigid and created unnecessary duplication)