Added DNSpolicy and DNSConfig overrides

[Eokye]

What does this PR do?

CECO-1252(https://datadoghq.atlassian.net/browse/CECO-1252
DNS config and DNS policy overrides were migrated to v2 from v1. This change fixes that.

A brief description of the change being made with this pull request.
DNS config + policy added to overrides and unit tested.

Motivation

What inspired you to submit this pull request?
#1144
https://datadoghq.atlassian.net/browse/CONS-6318

Additional Notes

Anything else we should know when reviewing?

Minimum Agent Versions

Are there minimum versions of the Datadog Agent and/or Cluster Agent required?

• Agent: vX.Y.Z
• Cluster Agent: vX.Y.Z

Describe your test plan

Used this manifest for the datadog-agent on a kind local cluster:

apiVersion: datadoghq.com/v2alpha1
kind: DatadogAgent
metadata:
  name: datadog
spec:
  override:
    nodeAgent:
      image:
        name: gcr.io/datadoghq/agent:7.55.0-rc.3
      dnsPolicy: ClusterFirstWithHostNet
      dnsConfig: 
        nameservers:
        - 10.9.8.7
        - 10.9.7.4
    clusterAgent:
      image:
        name: gcr.io/datadoghq/cluster-agent:7.55.0-rc.3
    clusterChecksRunner:
      image:
        name: gcr.io/datadoghq/agent:7.55.0-rc.3
  global:
    clusterName: kind-control
    kubelet:
      tlsVerify: false
    site: datadoghq.com
    credentials:
      apiSecret:
        secretName: datadog-secret
        keyName: api-key

The resulting change in the agent pod CRD:

  dnsConfig:
    nameservers:
    - 10.9.8.7
    - 10.9.7.4
  dnsPolicy: ClusterFirstWithHostNet

Checklist

• PR has at least one valid label: bug, enhancement, refactoring, documentation, tooling, and/or dependencies
• PR has a milestone or the qa/skip-qa label

[github-actions]

This pull request does not contain a valid label. Please add one of the following labels: bug, enhancement, refactoring, documentation, tooling, dependencies

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 51.51515% with 16 lines in your changes missing coverage. Please review.

Project coverage is 59.30%. Comparing base (c46b61d) to head (8eac693).
Report is 8 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1233      +/-   ##
==========================================
- Coverage   59.33%   59.30%   -0.03%     
==========================================
  Files         177      177              
  Lines       22371    22390      +19     
==========================================
+ Hits        13273    13279       +6     
- Misses       8286     8299      +13     
  Partials      812      812              

Flag	Coverage Δ
unittests	59.30% <51.51%> (-0.03%)	⬇️

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

Files	Coverage Δ
apis/datadoghq/v1alpha1/datadogagent_types.go	100.00% <ø> (ø)
apis/datadoghq/v2alpha1/datadogagent_types.go	100.00% <ø> (ø)
...ntrollers/datadogagent/override/podtemplatespec.go	72.72% <100.00%> (+0.56%)	⬆️
controllers/datadogagent_controller.go	70.53% <100.00%> (-0.38%)	⬇️
...ontrollers/datadogagent/controller_reconcile_v2.go	53.91% <75.00%> (+0.37%)	⬆️
pkg/plugin/common/client.go	0.00% <0.00%> (ø)
pkg/config/config.go	0.00% <0.00%> (ø)

... and 1 file with indirect coverage changes

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