Add php-fileinfo extension support

[erseco]

This PR adds fileinfo extension support to php-wasm across PHP 8.0 to 8.5.

I need this for two playground-style implementations I am building, inspired by WordPress Playground:

• facturascripts-playground
• omeka-s-playground

These projects rely on fileinfo for real-world application compatibility:

• https://github.com/erseco/facturascripts-playground
• https://github.com/ateeducacion/omeka-s-playground

The PR includes:

• build configuration for WITH_FILEINFO
• package/workspace registration
• versioned module loaders for PHP 8.0–8.5
• package metadata and docs
• tests covering extension loading and basic finfo usage

Thanks for your work on php-wasm.