Remove redundant cadvisor relabel rules in alloyModule

[PaulFarver]

Thanks for maintaining this awesome chart! It has saved us a lot of trouble ❤️

We currently have trouble with our openshift clusters, where cadvisor does not populate the image label on container_network_.* metrics for some reason. We saw the same problem with v1 of the chart, but were able to work around it with dropEmptyImageLabels: false and an extraMetricProcessingRules

The options in the k8s-monitoring chart v2:

cadvisor.metricsTuning.dropEmptyContainerLabels
cadvisor.metricsTuning.dropEmptyImageLabels
cadvisor.metricsTuning.normalizeUnnecessaryLabels
cadvisor.metricsTuning.keepPhysicalFilesystemDevices
cadvisor.metricsTuning.keepPhysicalNetworkDevices

currently do not seem to have an impact on how alloy behaves in reality, because these rules are always included through the -alloy-module-kubernetes configmap.

Looking at our output k8s-monitoring-alloy-metrics configmap, we have this:

data:
  config.alloy: |-
    ...
    // Feature: Cluster Metrics
    declare "cluster_metrics" {
      argument "metrics_destinations" {
        comment = "Must be a list of metric destinations where collected metrics should be forwarded to"
      }

      remote.kubernetes.configmap "kubernetes" {
        name = "k8s-monitoring-alloy-module-kubernetes"
        namespace = "k8s-monitoring"
      }

      import.string "kubernetes" {
        content = remote.kubernetes.configmap.kubernetes.data["core_metrics.alloy"]
      }
    ...

The k8s-monitoring-alloy-module-kubernetes includes the drop rules, but we cannot disable these

charts/k8s-monitoring/charts/feature-cluster-metrics/templates/_cadvisor.alloy.tpl and charts/k8s-monitoring/alloyModules/modules/kubernetes/core/metrics.alloy seem to have the same set of rules, but charts/k8s-monitoring/charts/feature-cluster-metrics/templates/_cadvisor.alloy.tpl is configurable

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[petewall]

Thanks, but in #1257, I'm actually breaking the use of alloyModules for cadvisor. That PR will have a more permanent and cleaner solution.

[PaulFarver]

@petewall Cool. Looking forward to it 👍
I'll close this PR, then

[petewall]

This should be doable now with the 2.0.12 release!