def getConfigurationOptions():
    """
        Retrieve all known node configuration options.

        The returned dictionary holds the possible node configuration options
        by option name. The value of each entry represents the specifics for
        that option in a dictionary:

         - C{'type'} (C{str}): The option's type (see
           L{Field<wokkel.data_form.Field>}'s doc string for possible values).
         - C{'label'} (C{unicode}): A human readable label for this option.
         - C{'options'} (C{dict}): Optional list of possible values for this
           option.

        Example::

            {
            "pubsub#persist_items":
                {"type": "boolean",
                 "label": "Persist items to storage"},
            "pubsub#deliver_payloads":
                {"type": "boolean",
                 "label": "Deliver payloads with event notifications"},
            "pubsub#send_last_published_item":
                {"type": "list-single",
                 "label": "When to send the last published item",
                 "options": {
                     "never": "Never",
                     "on_sub": "When a new subscription is processed"}
                }
            }

        @rtype: C{dict}.
        """
