Add Support for New Parts Kit UI - Craft 4

[joshuapease]

We've developed a new UI for our parts kit that is decoupled from this Craft Module.

Instead, it's a script tag and custom element that can be added to any type of CMS.

• https://github.com/vigetlabs/parts-kit

To integrate, we need to include the appropriate script, and also provide a JSON endpoint for the Parts Kit UI to consume.