feat: Add comment remove feature

[yamadashy]

Fix: #2

Key changes:

1. Added removeComments option to the configuration
2. Implemented comment removal for various file types (e.g., Python, JavaScript, HTML, CSS)
3. Updated README with information about the new feature
4. Added tests for the new functionality

Usage:

Set output.removeComments to true in your repopack.config.json file to enable comment removal:

{
  "output": {
    "removeComments": true
  }
}

This feature helps reduce the size of the output file and focuses on the essential code content, which can be beneficial for AI processing.