Add TypeScript and ES6 support

[taehunss]

I've developed a TypeScript version of reverse-tunnel-ssh by building upon your excellent work in a new repository. I've added full TypeScript support, ES6 module compatibility, and comprehensive type definitions while maintaining the original functionality.

I would be truly grateful if you could take a moment to review this implementation. Your feedback would be incredibly valuable, especially since this work is based on your foundational code.

Thank you for creating such a useful library in the first place. I hope these additions might be helpful to the community and potentially to your project as well.

Changes include:

• Full TypeScript conversion with type definitions
• ES6 module support (import/export)
• Declaration file (index.d.ts) for improved IDE integration
• Updated documentation with TypeScript usage examples
• Build system setup with tsconfig.json
• Maintained original API signature for backward compatibility
  These improvements enhance developer experience with features like code completion, type checking, and better error prevention, all while preserving the core functionality of the original library.

https://github.com/taehunss/reverse-tunnel-ssh