First-class experience builder support

Motivation

Experience builder (short XB) is currently in development and the 1.0 release is scheduled for October, at Drupalcon Vienna.

We want to integrate with it nicely and enable the following use-cases:

• Expose (global, custom-elements) Vue components of a nuxt frontend to XB, such that they show up as placeable components
• Render XB preview with Nuxt, to have a proper preview during editing
• Render XB pages with Lupus Decoupled Drupal, with support for blocks, Vue components as well is in-code (P)React components
• 2nd prio: Enable using Vue in in-browser code-components and enable server-rendering them

Proposed resolution

1. Prototype with Twig SDC components to have nuxt vue-components rendered in preview
2. Render XB-render array into custom element responses
3. New XB component-source for Nuxt/flexible JavaScript components

Remaining tasks

Clarify how to re-use Nuxt bundles to render XB-components during preview