Add support for creating list and adding items to it immediately

[engram-design]

Similar to #93 and #81 and will likely require some centralised mechanism to keep these things organised

[jckvnr]

This would be awesome - I have a lot of clients requesting this functionality

[martyspain]

I've done this with Wishlist using JS and Promises with the existing endpoints and that works well enough, but it would be nice to have official support for creating a list and adding an item to it in one go.

[estebancastro]

@martyspain Can you please show me an example of how you do create the list and add the item it immediately with JS and Promises? Thank You.

note: I don't use the form element to Add, Remove, Update or Toggle items, simply I use the URL, like:

{% for entry in craft.entries.section('news').all() %}
    {% set item = craft.wishlist.item(entry.id) %}
    <a href="{{ item.addUrl() }}">Add to List</a>
{% endfor %}

so I don't know how trigger the actions through JavaScript like this example: https://verbb.io/craft-plugins/wishlist/docs/template-guides/managing-items#submit-with-javaScript

[engram-design]

Added in 3.0.0