Preparatory refactoring for zcash/librustzcash#1673 #6356

Job	Run time
Bitrot check	1m 34s
Build target wasm32-wasi	55s
Latest build on ubuntu-latest	2m 10s
Build target thumbv7em-none-eabihf	31s
Latest build on windows-latest	4m 43s
Latest build on macOS-latest	1m 43s
Test no-Orchard on Linux	4m 40s
Check ZFuture build on Linux	28s
Test Orchard on Linux	6m 33s
Test no-Orchard on macOS	6m 14s
Check ZFuture build on macOS	30s
Slow Test Orchard on Linux	4m 24s
Test NU7 on Linux	6m 40s
Test Orchard on macOS	8m 35s
Slow Test NU7 on Linux	4m 24s
Check ZFuture build on Windows	3m 0s
Test no-Orchard on Windows	10m 55s
Clippy (MSRV)	1m 22s
Test Orchard on Windows	14m 2s
Clippy (beta)	12s
Test NU7 on Windows	13m 35s
Intra-doc links	2m 19s
Code coverage	1h 24m 23s
Rustfmt	15s
protobuf consistency	1m 6s
UUID validity	6s
Required status checks have passed	1s
	3h 5m 20s

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