fix(publick8s,privatek8s) ensure datadog setup works on AKS (Azure Linux, Admission Controller)

[dduportal]

Follow up of #5132
Related to jenkins-infra/helpdesk#3823

This PR ensures that datadog installation works as expected in our AKS clusters by following datadog recommendations:

• First change allows datadog agent to run on Azure Linux (ref. chore(privatek8s): change from ubuntu to azure linux the os for the nodes azure#662). It applies the datadog troubleshooting trick (https://docs.datadoghq.com/agent/troubleshooting/hostname_containers/?tab=helm#accessing-the-container-runtime-api) to use the container runtime API when resolving the hostname.
  • Fixes the error message Error: Error while getting hostname, exiting: unable to reliably determine the host name. You can define one in the agent config file or in your hosts file in the datadog-agent pod logs (when it is in CrashLoopBackOff)
• Second change ensures that the AKS admission controller works with datadog. It follows the datadog official instructions for AKS (ref. https://docs.datadoghq.com/containers/kubernetes/distributions/?tab=helm#AKS)

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Thanks @MarionPlt for the rubber ducking on this one!

[dduportal]

Force merging:

• To fix the main branch failure from fix(privatek8s/datadog) ensure datadog agent runs on all nodes by updating tolerations #5132 as the datadog agents on the Azure Linux pool will fail (and the helmfile apply will fail as well)
• Tested with success in production