feat(generation): add support for TypeScript types generation

[innocenzi]

This pull request adds support for generating TypeScript definitions out of PHP classes and enums.

Documentation: https://github.com/tempestphp/tempest-framework/blob/feat/typescript-codegen/docs/2-features/18-typescript.md

---

Running the generate:typescript-types command will create a types.d.ts file at the root of the project, with namespaced definitions:

/*
|----------------------------------------------------------------
| This file contains TypeScript definitions generated by Tempest.
|----------------------------------------------------------------
*/

export namespace App {
  export interface Settings {
    theme: Theme.Theme;
    sidebar_open: boolean;
    last_edited_at: string;
  }
  export interface Permission {
    name: string;
  }
  export interface User {
    settings: Settings;
    permissions: Permission[];
  }
}

export namespace App.Theme {
  export type Theme = 'dark' | 'light';
}

This is configurable by creating a config returning NamespacedTypeScriptGenerationConfig or DirectoryTypeScriptGenerationConfig. The latter generates a directory structure in ./types that's importable instead of .d.ts files:

types
└── app
    ├── index.ts
    └── theme
        └── index.ts

To mark a class for generation, it needs to have a #[AsType] attribute. However, I plan to implement heuristics (eg. the class only has public readonly properties) to automatically convert classes without having to add an attribute.