Support KSMCore in DCA

[ahmed-mez]

What does this PR do?

• Support running KSM core in the Cluster Agent (default mode).
• Fixed KSM RBACs
• Refactored the KSM code cluster-check mode

Motivation

The default mode should only require deploying the Cluster Agent

Describe your test plan

• Configure the kubeStateMetricsCore feature section in the DatadogAgent spec

  features:
    kubeStateMetricsCore:
      enabled: true

Case 1: undefined kubeStateMetricsCore.clusterCheck + cluster check runners enabled, the ksm check runs as a clustercheck
Case 2: undefined kubeStateMetricsCore.clusterCheck + cluster check runners disabled, the cluster agent runs the ksm check
Case 3: kubeStateMetricsCore.clusterCheck is true: the ksm check runs as a clustercheck
Case 4:kubeStateMetricsCore.clusterCheck is false: the cluster agent runs the ksm check

Important: Make sure this PR solves the bug reported in #307

[codecov-commenter]

Codecov Report

Merging #330 (409265d) into main (2b31269) will increase coverage by 25.80%.
The diff coverage is 64.10%.

@@             Coverage Diff             @@
##             main     #330       +/-   ##
===========================================
+ Coverage   37.41%   63.22%   +25.80%     
===========================================
  Files          62       60        -2     
  Lines       11053     6602     -4451     
===========================================
+ Hits         4136     4174       +38     
+ Misses       6620     2125     -4495     
- Partials      297      303        +6     

Flag	Coverage Δ
unittests	63.22% <64.10%> (+25.80%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
api/v1alpha1/datadogagent_types.go	100.00% <ø> (ø)
controllers/datadogagent_controller.go	60.60% <ø> (ø)
controllers/datadogagent/clusteragent.go	69.76% <28.57%> (-0.29%)	⬇️
api/v1alpha1/datadogagent_default.go	79.26% <60.00%> (-0.26%)	⬇️
...ntrollers/datadogagent/clusterchecksrunner_rbac.go	64.10% <60.00%> (+8.54%)	⬆️
controllers/datadogagent/kubestatemetrics.go	85.39% <68.33%> (-8.52%)	⬇️
controllers/datadogagent/utils.go	82.73% <100.00%> (+0.01%)	⬆️

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