MinIO: Add Virtual Service

Add an optional Virtual Service to the MinIO instance

minio:
  instance:
    istio:
      enabled: true
      gateways:
      - istio-system/main
      hosts:
      - {{ name | default "minio" }}.{{ .Values.hostname }}

Add a virtual service to the minio instance chart that we can use as follows:

minio:
  instance:
    istio:
      enabled: true
      gateways:
      - istio-system/main
      hosts:
      - minio.{{ .Values.hostname }}

Similar to what @iahmad did here: https://repo1.dso.mil/platform-one/big-bang/apps/core/elasticsearch-kibana/-/merge_requests/20/diffs#679c9c413d4749f4bd9d593879d89e405b2e471e