feat!: Add support for Nuxt 3

[dankerow]

This PR enables this module to work for Nuxt 3.

Notable changes

• Uses @nuxt/module-builder to build module.
• Refactor structure (lib -> src, templates -> runtime)
• Rewrite in TypeScript
• Move from templating options to runtime config

TODO

• Re-enable test suite (https://github.com/nuxt/framework/pull/2952)

[DenchiUA]

any updates?

[johannschopplich]

@DenchiUA You can use nuxt-gtag in the meanwhile. It's a native Gtag integration for Nuxt 3.