Add configurable scheme for webserver probes

[dan-vaughan]

We want to be able to terminate TLS at the webserver pod, which requires configuring the liveness and readiness probes to use https.

• Add configurable scheme to webserver probes
• Update values schema
• Add unittest

[potiuk]

It's not the best idea to use TLS termination in the webserver. Usually in K8S this should happen in the ingress and very rarely (if at all) you use TLS termination in application.

Why would you want to do this?

[dan-vaughan]

The k8s security standards for the company I work for require us to terminate TLS at the pod to prevent unencrypted ingress -> pod communication

[potiuk]

Interesting. I guess I will leave it to @jedcunningham and @ephraimbuddy to decide if they want to merge it, I see that might be useful for such level of a bit "paranoid" security.

Can you please fix the static checks and tests however @dan-vaughan

[potiuk]

Static checks are still failing. I suggest to rebase and install/run pre-commit before that.

[dan-vaughan]

Hey @potiuk, I've fixed the failing static checks, please let me know if there's anything else you need from me