Merge branch '3475363-stackblitz' into '0.x'

.tugboat/config.yml

components/astro/preact/preact_counter.component.yml

components/astro/preact/preact_counter.twig

components/astro/preact/preact_two_column.component.yml

components/astro/preact/preact_two_column.twig

components/astro/svelte/svelte_counter.component.yml

components/astro/svelte/svelte_counter.twig

components/astro/svelte/svelte_two_column.component.yml

components/astro/svelte/svelte_two_column.twig

composer.json

experience_builder.info.yml

experience_builder.libraries.yml

experience_builder.module

experience_builder.routing.yml

src/Controller/AstroUploadController.php

src/Controller/ExperienceBuilderController.php

ui/index.html

ui/package-lock.json

ui/package.json

ui/src/app/store.ts