Consolidate shared code of onboarding flutter and onboarding cli to a new package.

[sitaram-kalluri]

Is your feature request related to a problem?

Currently, there is redundancy in the onboarding code between the onboarding Flutter and onboarding CLI. To enhance maintainability, relocate the common code to a new package.

Progress Tracker:

• [x] Create a new package and move relevant code into it
• [x] Modify/optimize package design (so that register_cli and onboarding_flutter can both consume it without issues)
• [x] In-code docs
• [x] unit tests
• [x] Manual testing
• [x] docs (readme, changelog, etc)
• [x] Inclusion of this package and its tests into GitHub actions
• [ ] Integration testing (testing apps/cli's functioning with this package as dependency_override)
• [ ] Publish to pub.dev

[murali-shris]

Registrar related code:

• onboarding_cli/register_cli.dart

  • get free atsigns /v3/get-free-atsign/
  • register atsign /v3/register-person
  • validate otp /v3/validate-person

• onboarding_cli/onboarding_util.dart

  • getCramUsingOtp /v3/authenticate/atsign
  • getCramKey /v3/authenticate/atsign/activate

• at_onboarding_flutter/free_atsign_service.dart

  • get free signs /v2/get-free-atsign
  • authenticate /v2/login/atsign
  • register atsign /v2/register-person
  • validate atsign /v2/validate-person
  • verify atsign /v2/login/atsign/validate

[srieteja]

Common code has been moved to a new package "at_register" [not updated to git yet]. Testing integration with register_cli and the onboarding_flutter.

[srieteja]

Implementation of the new AtRegister package has been completed and is currently being tracked in https://github.com/atsign-foundation/at_libraries/pull/508. Assigning 1 sprint point to handle any changes required as part of pr review.