Add extensions on `DateTime` and `List` #486

Job	Run time
build_checkout (dev, ubuntu-latest)	2m 28s
build_checkout (dev, windows-latest)	6m 33s
build_checkout (dev, macos-latest)	3m 8s
build_fetch (ubuntu-latest)	43s
build_fetch (windows-latest)	1m 28s
build_fetch (macos-latest)	45s
build_local (ubuntu-latest)	1m 46s
build_local (macos-latest)	1m 40s
build_local (windows-latest)	4m 24s
	22m 55s

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