Ensure protocols are explicitly declared where possible for Istio Services

Protocols are not explicitly declared for Istio Services. If protocol cannot be determined automatically, all traffic is treated as plain TCP traffic which is not the most secure protocol.

Protocols can be specified manually in the Service definition. This can be configured in two ways:

1. By the name of the port: name: [-].
2. In Kubernetes 1.18+, by the appProtocol field: appProtocol: .

References:
https://istio.io/latest/docs/ops/configuration/traffic-management/protocol-selection/
https://kubernetes.io/docs/concepts/services-networking/service/