Register new feature with cloud connector for Duo Workflow Service

Per https://docs.gitlab.com/ee/development/cloud_connector/#register-new-feature-for-gitlabcom we need to register a new feature and the unit primitives for Duo Workflow Service.

More details:

1. https://gitlab.com/gitlab-org/gitlab/-/blob/e064fcb837f3c43e5062dbcea032818ab184a80b/ee/lib/ai/duo_workflow/duo_workflow_service/client.rb#L52
2. https://gitlab.com/gitlab-org/duo-workflow/duo-workflow-service/-/blob/6ca6a72e6ae97778f79e5f05524a80b75594d981/duo_workflow_service/gitlab_features.py#L27