tests: Add E2E test for net-attach-def lifecycle

[ormergi]

Rebased on (#13, first five commits)

This PR bootstrap Ginkgo e2e test suite and tests the OverlayNetwork corresponding NetworkAttachmentDefinition lifecycle; where the controller create/delete NAD when OverlayNetwork is created/delteted.

The test suite create Namspace "overlay-network-tests" for tests and deletes it when the test suite finish.

How to run tests:
make functests

[AlonaKaplan]

Please run the tests a project admin and not cluster-admin.

Chatgpt example of how it should be done-
Create a kubeconfig file for the project admin. Save it as kubeconfig-admin.yaml:
yaml
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apiVersion: v1
kind: Config
clusters:

• name: your-cluster-name
  cluster:
  server: https://your-cluster-server
  certificate-authority-data:
  users:
• name: project-admin
  user:
  client-certificate-data:
  client-key-data:
  contexts:
• name: project-admin-context
  context:
  cluster: your-cluster-name
  user: project-admin
  current-context: project-admin-context
  Replace placeholders like your-cluster-name, https://your-cluster-server, , , and with the actual values.

Update your test code to use this custom kubeconfig file:
go
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import (
"k8s.io/client-go/kubernetes"
"k8s.io/client-go/tools/clientcmd"
"k8s.io/client-go/util/homedir"
"path/filepath"
)

func getClientForProjectAdmin() (kubernetes.Interface, error) {
adminKubeconfigPath := "/path/to/kubeconfig-admin.yaml" // Update with the correct path

// Use the in-cluster config if running within a cluster, otherwise use the specified kubeconfig
config, err := clientcmd.BuildConfigFromFlags("", adminKubeconfigPath)
if err != nil {
	return nil, err
}

mgr, err := ctrl.NewManager(config, ctrlOptions)
if err != nil {
	return nil, err
}

return client.New(mgr.GetConfig(), client.Options{Scheme: mgr.GetScheme(), Mapper: mgr.GetRESTMapper()})

}