hal_json_style: support a custom status message/level on edit
Jérome Perrin authored
This allow edit scripts or interactions to change the status message or
the status level using the same way as workflow scripts: script can set
the status text in request['portal_status_message'] and the status level
in request['portal_status_level'].

Note that part of this was already checked in accidentally in 97c40dcb

/reviewed-on nexedi/erp5!1052
159daa14