Make `hostNetwork` configurable in the helm charts

[aramase]

secrets-store-csi-driver-provider-azure/charts/csi-secrets-store-provider-azure/templates/provider-azure-installer.yaml

Line 44 in 4ef5092

hostNetwork: true

hostNetwork: true is only required when using pod identity to access key vault. We should make this value configurable so users can set it to false if they're not using pod identity (also this is deprecated and will be removed completely in the future).