generated_plugin_registrant library Null safety

1. now8
2. generated_plugin_registrant library

now8 package

1. Libraries
2. arrivals
3. common
4. configure_nonweb
5. configure_web
6. data
7. domain
8. exceptions
9. favorites
10. generated_plugin_registrant
11. home
12. icons
13. main
14. providers
15. stop
16. welcome