Add and use a container() method to find a field element's parent

Some methods are extremely opinionated in finding form element containers, and they aren't even all necessarily of the same opinion.

The `showField`/`hideField` methods assume the parent element.  The `orderFields` method assumes the parent, but specifically a div or section...

We should probably introduce a generic `container` method that finds a form elements containing element.  The definition of which is something along the lines of...  "The closest element that contains both this form element and its label"

We should then update `showField`, `hideField`, and `orderFields` to use this new method.