Add l4lb-class test scenario

[08volt]

What type of PR is this?

/kind feature

What this PR does / why we need it:

This PR adds a new test scenario for l4lb-class in ClusterLoader2. It includes configuration for testing LoadBalancers allowing to specify a loadBalancerClass, along with corresponding deployment and service templates.

Which issue(s) this PR fixes:

Fixes #3934

Special notes for your reviewer:

This test scenario is designed to validate the behavior of custom load balancer classes in large scale clusters.

[k8s-ci-robot]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[08volt]

Hi @mborsz @wojtek-t could you please have a look? thank you

[mborsz]

/assign @Qqkyu

[Qqkyu]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: 08volt, Qqkyu

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• clusterloader2/OWNERS [Qqkyu]

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[k8s-ci-robot]

@08volt: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-perf-tests-gce-master-scale-performance-100	6280982	link	unknown	/test pull-perf-tests-gce-master-scale-performance-100

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

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