MCAD test/perf-test docs and yaml need updating

[jbusche]

Describe the Bug

Noticed multiple changes that need to be made for the multi-cluster-app-dispatcher/test/perf-test scripts

1. preempt-exp-kwok.yaml and preempt-exp.yaml need to have the following line removed or commented out:

    Items: []

2. The install method for kwok just changed, and the old version doesn't work, so the instructions need to be updated here in simulatingnodesandappwrappers.md
   Latest (and simplare instructions are here: https://kwok.sigs.k8s.io/docs/user/kwok-in-cluster/

Codeflare Stack Component Versions

Please specify the component versions in which you have encountered this bug.

Codeflare SDK: n/a
MCAD: quay.io/jbusche/mcad-controller:pr-12
Instascale: quay.io/jbusche/instascale:pr-02
Codeflare Operator: n/a
Other:

Steps to Reproduce the Bug

./perf.sh 
Checking whether we have a valid cluster login or not...

Nice, looks like you're logged in
Checking MCAD Controller installation status

Nice, MCAD Controller is installed

How many appwrapper jobs do you want?2
jobs number is 2
 
Jobs started at: 17:29:18
 
Submitting job 1
Error from server (BadRequest): error when creating "/root/MCAD/multi-cluster-app-dispatcher/test/perf-test/preempt-exp.yaml": AppWrapper in version "v1beta1" cannot be handled as a AppWrapper: strict decoding error: unknown field "spec.resources.Items"

What Have You Already Tried to Debug the Issue?

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Expected Behavior

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Screenshots, Console Output, Logs, etc.

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Affected Releases

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Additional Context

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OC 4.13.4

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