Update module template

[atinux]

https://github.com/nuxt/starter/tree/module

• Improve readme (Add description, installation, usage, module development and note for module-builder)
• Add @nuxt/eslint-config
• Setup a release script (release-it or changelogen)
• Add a test with @nuxt/test-utils

[pi0]

For the release script, we should use changelogen --release (example). It guarantees forward compatibility with module builder integration and consistent changelogs we can render on website.

Entry module.ts should also be simplified a little bit using kit and remove defaults I see are often preserved in published modules.

I think would be also a good time to introduce basic prettier wyt @danielroe ?