[ADD PACKAGE] font_mapper

[congthanhng]

Note: To add multiple packages, open a separate issue for each package.

Details of the package(s) you want to add

• font_mapper
• https://pub.dev/packages/font_mapper
• fonts
• A Dart CLI tool to scan font files and auto-generate the fonts: section in your pubspec.yaml.

[ashitaprasad]

Thanks for submitting the package @congthanhng
Will close this issue once it is live on the website after review.

[ashitaprasad]

The package is now available on Flutter Gems 🎉
https://fluttergems.dev/packages/font_mapper/