Add `cppwinrt` crate and sample #68

Job	Run time
check (1.70.0, windows-latest)	47s
check (1.70.0, ubuntu-latest)	27s
check (stable, windows-latest)	58s
check (stable, ubuntu-latest)	23s
check (nightly, windows-latest)	48s
check (nightly, ubuntu-latest)	26s
	3m 49s

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