#3442 - Add custom sub-fields to ticket types

I'll leave this open, however it is currently possible with a small amount of code using the Decision Tree system, which can sit in front of tickets.

See our contact page code for an example:
https://github.com/ocproducts/composr/blob/master/pages/minimodules_custom/contact.php

~ 95% of that file is just defining the settings for our contact tree.

The core code pattern in a minimodule is just...

<?php

$decision_tree = array(
...
);

require_code('decision_tree');
$ob = new DecisionTree($decision_tree);
$tpl = $ob->run();
$tpl->evaluate_echo();