[feature] helm: add service.extraPorts to all components

[TheRealNoob]

What this PR does

In the Helm chart, add service.extraPorts to all components that allow defining extraContainers. The intention being that people may expose additional ports on the Pod, and that should be exposed from the Service as well.

I haven't bumped the chart version, could you tell me what it should be bumped to? I'm not familiar with the format being used.

Which issue(s) this PR fixes or relates to

Didn't open one

Checklist

• Tests updated.
• Documentation added.
• CHANGELOG.md updated - the order of entries should be [CHANGE], [FEATURE], [ENHANCEMENT], [BUGFIX].
• about-versioning.md updated with experimental features.

[CLAassistant]

All committers have signed the CLA.

[narqo]

Thank you for working on the PR. Before moving the changes further, could you provide more details about the problem you were solving

[..] The intention being that people may expose additional ports on the Pod

Is this a theoretical case? Or can you share a practical scenario where ports from mimir components were missing and needed to be exposed to the cluster?

[TheRealNoob]

@narqo Thank you for having a look. The use-case that I'm working on is exposing prometheus and alertmanager to the internet behind an oauth2 sidecar. I'm setting them up under new ingress objects so as to not interfere with the main ingress which I have using basicAuth authentication.

I saw in the chart that there are already comments in place on the alertmanager.extraContainers spec for exactly this kind of sidecar, in which case this PR is just an expansion of that intention.

Let me know if you need me to go into any more detail. In short, if someone adds an extraContainer that exposes a new port, there is a very high likelihood that they'll need to expose it on the SVC as well.