Update listener internal slots to map<name, structure>

Currently internal slots for [[readHandlers]], [[writeHandlers]], etc. are a map from name to a handler function.

Besides that function, the steps require saving |options| and other information as well.
So the internal slots will need to contain an object like

dictionary HandlerData {
    required function handler;
    sequence<InteractionOptions> subscriberOptions;
    sequence<any> subscriberData;
}

We could also add the |interaction| for convenience, but it can me retrieved using |name|.

Start by locating the listener internal slot definitions and the steps that read or write [[readHandlers]], [[writeHandlers]], and related maps. Update the slot values to retain the handler, subscriberOptions, and subscriberData described in the issue, then verify that all affected listener steps use the new structure.