Add `labels` to Helm chart.

[hongyiweiwu01]

/feature

Is your feature request related to a problem? Please describe.
I'm hoping to add certain labels to pods spawned by the Helm chart. This helps us add these pods into our service mesh.

Describe the solution you'd like in detail
node.labels, controller.labels, and mountpointPod.labels should be added to the Helm chart. Their values should be added to the corresponding deployment/daemonset templates.

Describe alternatives you've considered
N/A.

Additional context
Would love to provide a PR so please let me know!

[dannycjones]

Hey @hongyiweiwu01. Thanks for your interest!

For context, the Helm chart will create the node and controller deployments/daemonsets but the Mountpoint pods are created by the CSI driver (i.e. Golang code).

mountpoint-s3-csi-driver/pkg/podmounter/mppod/creator.go

Lines 110 to 113 in d5e57d1

	Labels: map[string]string{
	LabelMountpointVersion: c.config.MountpointVersion,
	LabelCSIDriverVersion: c.config.CSIDriverVersion,
	},

We would welcome a contribution! I think it would be worth discussing here some ideas on what the config would look like (i.e. how would you use --set <VALUE> in Helm), how that would get passed in to the controller component, and then applied to the Mountpoint pods.

[dannycjones]

I'd also be interested in how we might test the change. We'll have tests that the correct labels are set today, but how do we test that labels are passed through and correctly applied?