Consolidate linux and windows containerd config templates #9231

Job	Run time
build / Build	7m 6s
Integration Tests (certrotation)	1m 11s
Integration Tests (cacertrotation)	1m 17s
Integration Tests (etcdrestore)	1m 41s
Integration Tests (localstorage)	1m 3s
Integration Tests (startup)	5m 55s
Integration Tests (custometcdargs)	28s
Integration Tests (etcdsnapshot)	7m 26s
Integration Tests (kubeflags)	6m 24s
Integration Tests (longhorn)	2m 21s
Integration Tests (secretsencryption)	2m 3s
Integration Tests (flannelnone)	55s
	37m 50s

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