appButton library Null safety

1. appmayor
2. appButton library

appmayor package

1. Libraries
2. addApp
3. addedApps
4. addIcons
5. app
6. appButton
7. appList
8. aprende
9. auth
10. battery
11. battery_indicator
12. button
13. buttons
14. cache_manager
15. card3d
16. colors
17. constants
18. contactbuttonOne
19. contactbuttonTwo
20. contactCard
21. contactList
22. customCard
23. customView
24. data
25. db_provider
26. emergency
27. facebookbutton
28. firebase_options
29. globals
30. main
31. notificationbadge
32. panel1
33. panel2
34. panel3
35. panel4
36. portalmayor
37. pushnotification
38. registerUser
39. remote_config_service
40. rutValidator
41. saludResponde
42. size_helpers
43. smslist
44. splash
45. title
46. user
47. userProvider
48. watch
49. webview
50. whatsappbutton
51. wrapper