Support custom labels and annotations for Deployments/StatefulSets

Allow users to configure additional labels and/or annotations on the Deployment/StatefulSet objects (not just for pods/services). This feature would be tremendously useful for environments that require certain labels to be set - currently the only alternative is to maintain a fork of the chart internally, which seems quite wasteful just to add a label.

Start by locating the chart templates that render Deployment and StatefulSet objects, then inspect how existing pod and service labels or annotations are configured. Done means users can provide additional values that appear on the Deployment or StatefulSet metadata without maintaining a chart fork.

Written by the indexing model from the issue text.