feat: support recursive file search

[thwonghin]

This PR supports putting enums / mixins / models in nested folders. This is particularly helpful to separate the models by domain folders:

- models
    - auth
        - Account.model.ts
        - VerificationToken.model.ts
    - order
        - Order.model.ts
        - OrderItem.model.ts  

[thwonghin]

Extend from this, I think we can allow customizing the paths with glob pattern, but that will be another PR.

And also we could define which file extensions we want to support (I guess typically .ts, .js and .mjs) and then we use some glob library to easily get all the file paths.

[ridafkih]

This is great, going to run some tests! We can absolutely support other file extensions, but you're right in that it should be another pull request. :)

[ridafkih]

Thanks so much, looks great!