feat: add an observability operator

[sduranc]

Description

• It adds an observability operator based on kube builder
• For the moment we only need to handle prom rules --> azure rule group
• It uses the azure sdk directly
• So far it has tests and not e2e tests completely, since this is still a WIP
• It uses azidentity, because we wanna run it with workload identity
• Note: this is really a draft, so I haven't taken the time to clean properly - there might be some outdated stuff here and there

Related Issue(s)

• #{913}

Verification

• Your code builds clean without any errors or warnings
• Manual testing done (required)
• [] Relevant automated test added (if you find this hard, leave it and we'll help out)
• All tests run green

Documentation

• User documentation is updated with a separate linked PR in altinn-studio-docs. (if applicable)

[khanrn]

I am kinda curious about the edge case of zero duration for Prometheus inputs. Specifically, cases like "0s", "0m", or an empty string. Shouldn't this ideally be parsed as zero duration, resulting in the ISO 8601 representation of PT0S? 🤔

In code it would look like this:

if isoDuration == "P" {
    isoDuration = "PT0S"
}

[sduranc]

Specifically, cases like "0s", "0m", or an empty string

The first 2 don't make sense in the context of promQL, but we can definitely add them to the tests.

[khanrn]

Regarding this: https://github.com/Altinn/altinn-platform/pull/1018/files#r1812522355

Also another test case may need to get added here:

{"0", "PT0S"},

[sduranc]

Go ahead, you can just add them. See what happens in those tests.