Add methods for building `ua::DataValue` with timestamps #758

Job	Run time
run (aarch64-apple-darwin, macos-latest)	5m 29s
run (armv7-unknown-linux-gnueabihf, ubuntu-latest)	6m 4s
run (x86_64-apple-darwin, macos-latest)	10m 12s
run (x86_64-pc-windows-msvc, windows-latest)	9m 49s
run (x86_64-unknown-linux-gnu, ubuntu-latest)	6m 0s
run (x86_64-unknown-linux-musl, ubuntu-latest)	4m 48s
	42m 22s

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