Add metrics for API calls

[dergeberl]

How to categorize this PR?

/kind enhancement

What this PR does / why we need it:

This PR adds metrics for API calls. Similar to the metrics in cloud-provider-stackit see https://github.com/stackitcloud/cloud-provider-stackit/tree/main/pkg/metrics

Special notes for your reviewer:

⚠️ I am not sure about the operationFromRequest, see also comment.

I tested that the metrics are created:

Breaking changes:

[ske-prow]

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[dergeberl]

I am not 100% sure about this. It kind of works but only in case all APIs follow that odd/even rule.
I copied this from https://github.com/stackitcloud/cloud-provider-stackit/blob/83f9aae577aa7e4a5b080cdbd076e6341aebd19f/pkg/metrics/http.go#L59

[ske-prow]

@dergeberl: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-application-load-balancer-controller-verify	ccc61b2	link	true	/test pull-application-load-balancer-controller-verify

Full PR test history. Your PR dashboard. Command help for this repository.
Please help us cut down on flakes by linking this test failure to an open flake report or filing a new flake report if you can't find an existing one. Also see the gardener testing guideline for how to avoid and hunt flakes.

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