NewDeploymentController creates a new DeploymentController.

FullDeploymentResyncPeriod means we'll attempt to recompute the required replicas of all deployments.

MaxRetries is the number of times a deployment will be retried before it is dropped out of the queue.

We must avoid creating new replica set / counting pods until the replica set / pods store has synced.

DeploymentController is responsible for synchronizing Deployment objects stored in the system with actual running replica sets and pods.