Issue382 limit scope

- [x] `config.scopes = ["@cnpm", "@cnpmtest"];` to use scope mode
- [x] only allowed sync none scope modules
- [x] `config.adaptScope` to redirect `@cnpm/private-package` => `private-package`, forward compatbility for update from lower version cnpmjs.org
- [x] `config.forcePublishWithScope` force normal users publish with scope
- [x] `private` mode only admins can publish, and admins can publish without scope
- [x] `public` mode everyone can publish, but normal users only allowed publish with scope, admins have permission to publish / unpublish without scope.