feat: allow custom base path

[freality]

🔗 Linked issue

Allow custom base path other than /api/auth #168

❓ 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

By allowing the user to configure a basePath, the user can implement their NuxtAuthHandler on any route they chose.

This PR adds an optional basePath to the module configuration object (with default /api/auth for backwards compatibility). It generates a #build/auth.config.mjs with #auth-config alias. And uses the configuration variable where needed.

Docs are also updated to include the new basePath configuration.

resolves #168

📝 Checklist

• I have linked an issue or discussion.
• I have updated the documentation accordingly.

[Hebilicious]

Hi, thanks for contributing.
This is looking great!
Looks like the tests are failing so this will need a bit more work.
Could you try to remove the ts-expect errors and add a declaration file to handle the config?

[freality]

Looks like the tests are failing so this will need a bit more work.

I'm seeing the same build error when run against the main branch.

[mdowton]

Really looking for the feature also is blocking our current work any update @Hebilicious