feat: watch metrics-config in agent mode

[antoinedeschenes]

Reopening #1899

What does this PR change?

• Allows agent mode to watch the metrics-config ConfigMap, this was unexpected as the costmodel execution behaves correctly. Documentation doesn't mention agent mode missing that feature.

Does this PR relate to any other PRs?

• fix: disabledMetrics cause panics #1897 indirectly, we're trying to disable a few metrics in agent mode and having issues

How will this PR impact users?

• Enables disabledMetrics support in agent mode

Does this PR address any GitHub or Zendesk issues?

• Closes ...

How was this PR tested?

Running locally port-forwarded to a remote cluster and Prometheus, with a provisioned metrics-config configmap.

• Log outputs:

  INF Starting metrics init with disabled metrics: [service_selector_labels statefulSet_match_labels 
  deployment_match_labels kube_namespace_labels kube_node_labels kube_pod_labels]
  

• curl localhost:9005/metrics output doesn't contain the above metrics once this PR is applied.

Does this PR require changes to documentation?

• No, there are no mentions of the missing feature in agent mode.

Have you labeled this PR and its corresponding Issue as "next release" if it should be part of the next Opencost release? If not, why not?

[AjayTripathy]

@mbolt35 is this something that makes sense for agentmode?

[AjayTripathy]

@nikovacevic actually since Bolt is out

[nikovacevic]

@AjayTripathy will try to get to it this week

[mattray]

Assigning to Kubecost Engineering for review

[nikovacevic]

Apologies, I did not get to this, obviously. @mbolt35 is back -- Bolt, do you want to sync on this, and decide together whether or not this makes sense?

[github-actions]

This pull request has been marked as stale because it has been open for 90 days with no activity. Please remove the stale label or comment or this pull request will be closed in 5 days.

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Name	Status	Preview	Comments	Updated (UTC)
opencost	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Feb 29, 2024 7:39pm

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
21.8% Coverage on New Code
2.3% Duplication on New Code

See analysis details on SonarCloud

[github-actions]

This pull request has been marked as stale because it has been open for 90 days with no activity. Please remove the stale label or comment or this pull request will be closed in 5 days.