refactor(@angular/cli): remove old package manager utilities #2904

Job	Run time
list	30s
workflow (build-unit-tests)	2m 31s
workflow (devkit-core-tests-rerun)	1m 37s
workflow (devkit-core-tests)	1m 33s
workflow (build-cli)	1m 45s
workflow (modules-builder-tests)	1m 55s
	9m 51s

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