🎩 What? Why?

Decidim won't run without the webpacker gem anymore.

Shouldn't it be a core dependency then rather than requiring everyone to add it manually as a dependency?

I also updated the app migration guide with some relevant parts as I went through it after #8180.

📌 Related Issues

• Related to Migrate to Webpacker #7464, Migrate to Webpacker (CSS and images) #7733, Webpacker clean Sprockets and update docs #7942, Docs: Update the module webpacker migration guide #8180

Testing

• Re-create the development app
• See that webpacker is working

📋 Checklist

• ❓ CONSIDER adding a unit test if your PR resolves an issue.
• ✔️ DO check open PR's to avoid duplicates.
• ✔️ DO keep pull requests small so they can be easily reviewed.
• ✔️ DO build locally before pushing.
• ✔️ DO make sure tests pass.
• ✔️ DO make sure any new changes are documented in docs/.
• ✔️ DO add and modify seeds if necessary.
• ✔️ DO add CHANGELOG upgrade notes if required.
• ✔️ DO add to GraphQL API if there are new public fields.
• ✔️ DO add link to MetaDecidim if it's a new feature.
• ❌AVOID breaking the continuous integration build.
• ❌AVOID making significant changes to the overall architecture.