feat: configurable generated file and directory paths

[BobbieGoede]

🔗 Linked issue

• Full server path is leaked/exposed on __NUXT__ through i18n.files #3234
• npm run generate produces absolute path to my language files #3188
• fix: node_modules paths in runtime configuration payload #3022

❓ Type of change

• 📖 Documentation (updates to the documentation, readme or JSdoc annotations)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality like performance)
• ✨ New feature (a non-breaking change that adds functionality)
• 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

Related to #3022 but does not resolve it.

Resolves #3234
Resolves #3188

This only changes the paths in the generated options to be relative, this is still not desirable but better than exposing absolute paths as it could expose sensitive information.

Since this also influences the paths found in the locales array returned by useI18n I have made this a configurable option with experimental.generatedLocaleFilePathFormat to prevent this being a breaking change, in the future I want to look into removing the paths entirely or hashing the file paths.

I'm not sure if there are use cases for end users to have access to the files property on the generated locale options.

📝 Checklist

• I have linked an issue or discussion.
• I have added tests (if possible).
• I have updated the documentation accordingly.

[BobbieGoede]

Setting back to draft status - the normalizedLocales in the generated options files need their paths processed as well.

[BobbieGoede]

Converting to draft again, the i18nModules langDir paths should be processed as well.