Specify `selector` for persistent volume claims

My team often has several development instances of RStudio Workbench deployed at any time. We'd like to be able to leverage creating the homeStorage persistent volume claim, but with NFS persistent volumes it's sometimes tricky to make sure that the claim binds to the correct volume. We leverage the selector feature of persistent volume to make sure the bind happens correctly.

For example, we define the spec for the PVC like so:

spec:
  accessModes:
  - ReadWriteMany
  resources:
    requests:
      storage: 1Mi
  selector:
    matchLabels:
      app.kubernetes.io/instance: my-workbench-deployment
      pv-role: home

and it then binds to a persistent volume matching those labels.

It would be helpful if we could define a selector block when creating a persistent volume claim, which would go here:

https://github.com/rstudio/helm/blob/f73fdd04cecfaead6d48f230e2ae722728448ed4/charts/rstudio-workbench/templates/pvc.yaml#L38

Here's the Kubernetes documentation for it: https://kubernetes.io/docs/concepts/storage/persistent-volumes/#selector

Start with charts/rstudio-workbench/templates/pvc.yaml at the referenced PVC spec. Read the surrounding template and determine how chart configuration is passed into it. Done means users can provide a Kubernetes selector for the homeStorage claim and the rendered PVC includes the requested selector fields.