Add hash method for quantities #758

Job	Run time
Julia min - windows-latest - default	12m 33s
Julia 1 - ubuntu-latest - default	3m 42s
Julia lts - macos-latest - default	3m 40s
Julia 1 - macos-latest - default	3m 3s
Julia lts - ubuntu-latest - default	3m 10s
Julia pre - macos-latest - default	3m 10s
Julia 1.8 - macos-latest - default	2m 47s
Julia pre - windows-latest - default	4m 56s
Julia lts - windows-latest - default	4m 36s
Julia min - ubuntu-latest - default	3m 32s
Julia 1 - windows-latest - default	4m 45s
Julia pre - ubuntu-latest - default	3m 46s
	53m 40s

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