Change namespace for form-fields from class (::xowiki::FormField) to ordinary Tcl namespace (::xowiki::formfield) to make it easier to create formfield classes in other packages. This allows the file xowiki/tcl/form-field-procs.tcl to be reloaded without swiping the namespace.
- improve handling for form-fields of type form_page (makes it easier to change the xowiki instance, from where the form is resolved) - better handling of nested package initialzations