helpers/get_user_agent library

1. ruut package
2. documentation
3. helpers/get_user_agent.dart

ruut package

1. Libraries
2. controllers/ruut_controller
3. helpers/file_picker_service
4. helpers/generate_random_string
5. helpers/get_user_agent
6. helpers/ruut_message_channel
7. models/ruut_user_model
8. ruut