optimize k8s config initialization

[karthikkurella]

Fix: #2597

#Problem:

• The LoadNodes function performs unnecessary Kubernetes (k8s) configuration loading routines even when the k8s driver is not in use, leading to performance overhead due to unnecessary YAML parsing.

Solution:

• Modify the LoadNodes function to conditionally execute k8s-specific logic only when the k8s driver is being used.

Changes:

Add Conditional Check:

• Check if the node's endpoint contains "kubernetes" before loading the k8s configuration.
• Move k8s Config Loading Logic:

Encapsulate the k8s configuration loading within the conditional check to prevent unnecessary operations.
This ensures that k8s-specific logic is only executed when required, reducing unnecessary overhead.

[karthikkurella]

@tonistiigi Please review the changes.

Thank you.

[crazy-max]

Sorry I missed this PR, I think we want to tend for the implementation from #2606 that moves k8s config handling to the driver package. But thanks!