Item12783: sort tabs for installed extensions

This has been a long-standing annoyance: tabs for extension-specific options
are sorted by the order in which their =Config.spec= files are read; that's
easy to implement but hard to read.

Implement a new option for configure sections to sort a section's child tabs
(specifically all but the first, as that's what we need here), called
SORTBUTFIRST.



git-svn-id: http://svn.foswiki.org/trunk@17361 0b4bb1d4-4e5a-0410-9cc4-b2b747904278