Change auto-following admin-selected accounts, show in recommendations (#16078)

app/controllers/api/v1/suggestions_controller.rb

app/lib/potential_friendship_tracker.rb

app/models/account_suggestions.rb

app/models/account_suggestions/global_source.rb

app/models/account_suggestions/past_interactions_source.rb

app/models/account_suggestions/setting_source.rb

app/models/account_suggestions/source.rb

app/models/account_suggestions/suggestion.rb

app/models/follow_recommendation.rb

app/models/form/admin_settings.rb

app/services/bootstrap_timeline_service.rb

app/validators/existing_username_validator.rb

app/views/admin/settings/edit.html.haml

config/locales/en.yml

config/settings.yml

spec/services/bootstrap_timeline_service_spec.rb