Automatically set Service protocol field (for istio support)

[thesuperzapper]

Checks

• I have checked for existing issues.
• This report is about the user-community Airflow Helm Chart.

Motivation

A number of issues have been raised about the names we use for service ports, not being compatible with istio requirements:

• Service Port Naming Not Compatible with Istio #499
• Has anyone been able to use this chart when running in a cluster with Istio? #510

Implementation

Rather than allowing users to rename ports (as proposed in #493), and potentially specify the wrong protocol, we can automatically specify the protocol field of ContainerPort v1 (added in K8S 1.18), by detecting if AIRFLOW__WEBSERVER__WEB_SERVER_SSL_CERT and AIRFLOW__WEBSERVER__WEB_SERVER_SSL_KEY are set with detection similar to our define "airflow.web.scheme", which is used in the webserver probe.

Are you willing & able to help?

• I am able to submit a PR!
• I can help test the feature!