3d Model Field

Adds Statamic 6 support by porting the Control Panel fieldtype from Vue 2 to Vue 3.

• Widen statamic/cms constraint to ^5.0|^6.0
• Migrate the CP fieldtype build from @vitejs/plugin-vue2 to @vitejs/plugin-vue (Vue 3), externalize Vue, and emit an IIFE bundle with the FieldtypeMixin banner shim
• Register model-viewer as a custom element in the Vue compiler
• Replace the removed toggle-input global with ui-switch
• Drop illegal this. references from templates (invalid in Vue 3)
• Register the component inside Statamic.booting()

Backwards compatible with Statamic 5.

• N/A Changelog not available.

New Statamic addon that uses google/model-viewer to display 3d models.