Add extensions on `DateTime` and `List` #476

Job	Run time
build_checkout (dev, ubuntu-latest)	2m 35s
build_fetch (ubuntu-latest)	46s
build_checkout (dev, windows-latest)	5m 4s
build_fetch (windows-latest)	1m 2s
build_local (ubuntu-latest)	1m 39s
build_checkout (dev, macos-latest)	2m 32s
build_fetch (macos-latest)	56s
build_local (macos-latest)	2m 40s
build_local (windows-latest)	4m 9s
	21m 23s

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