Change user settings to be stored in a more optimal way (#23630)

.rubocop.yml

.rubocop_todo.yml

app/controllers/api/v1/accounts/credentials_controller.rb

app/controllers/settings/preferences_controller.rb

app/lib/user_settings_decorator.rb

app/lib/user_settings_serializer.rb

app/models/concerns/has_user_settings.rb

app/models/user.rb

app/models/user_settings.rb

app/models/user_settings/dsl.rb

app/models/user_settings/glue.rb

app/models/user_settings/namespace.rb

app/models/user_settings/setting.rb

app/services/notify_service.rb

app/views/settings/preferences/appearance/show.html.haml

app/views/settings/preferences/notifications/show.html.haml

app/views/settings/preferences/other/show.html.haml

config/initializers/inflections.rb

config/settings.yml

db/migrate/20230215074327_add_settings_to_users.rb