Feature request: Add ability to include additional labels in generated resources

[Kevin Huber]

Is your feature request related to a problem? Please describe.
We currently have Gatekeeper constraints that filter resources by labels. However, the argocd-operator does not provide a way to add additional labels to the generated resources.

Describe the solution you'd like
We would like to add additional labels to the generated resources in a similar manner to what can be done with the Helm chart found here: https://github.com/argoproj/argo-helm/blob/main/charts/argo-cd/values.yaml#L47

Describe alternatives you've considered
None