functions/url_launcher_function library

1. checkout package
2. documentation
3. functions/url_launcher_function.dart

checkout package

1. Libraries
2. checkout
3. constants/colors
4. constants/images
5. constants/size_config
6. constants/ursl
7. database/db
8. functions/toasts
9. functions/url_launcher_function
10. models/config_data
11. models/products_model
12. models/self_data
13. widgets/button_Global