replace the setup-envtest shell script with the new binary

[raghavendra-talur]

This PR replaces the setup-envtest.sh script with the go binary that controller-runtime pkg has introduced to make setting up of the test env simpler. (kubernetes-sigs/controller-runtime#1488)

[openshift-ci]

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

[openshift-ci]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: raghavendra-talur
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[raghavendra-talur]

This should remain in draft until the following issue is fixed:
kubernetes-sigs/controller-runtime#1571