Move OnboardingProgress to modular design

.rubocop_todo/gitlab/namespaced_class.yml

.rubocop_todo/layout/line_length.yml

.rubocop_todo/layout/space_in_lambda_literal.yml

.rubocop_todo/rails/where_exists.yml

.rubocop_todo/rspec/context_wording.yml

.rubocop_todo/style/lambda.yml

app/helpers/learn_gitlab_helper.rb

app/models/namespace.rb

app/models/onboarding/progress.rb

app/models/onboarding_progress.rb

app/services/groups/create_service.rb

...ervices/namespaces/in_product_marketing_emails_service.rb

app/services/onboarding_progress_service.rb

db/docs/onboarding_progresses.yml

ee/app/models/sca/license_compliance.rb

ee/spec/helpers/ee/learn_gitlab_helper_spec.rb

ee/spec/models/sca/license_compliance_spec.rb

lib/learn_gitlab/onboarding.rb

spec/controllers/repositories/git_http_controller_spec.rb

spec/factories/onboarding/progresses.rb