Admin / Start Stream

Implement the GET /stream/{id}/start method of the streaming API in the controller using the DeploymentAdminService (to be created):

• get stream definition record from the storage service using the stream id (input parameter)
• extract deployment id and replicas from ExtensionProperties
• call DeploymentAdminService::startDeployment method passing deployment id and the number of replicas
• handle exceptions and return the appropriate HTTP code
• create tests for each possible return code