Rust

Enable optional value handling in emulated and bls12381 #183

Job	Run time
clippy	54s
test	4m 33s
msrv (emulated)	51s
msrv (uint64)	1m 10s
msrv (chunk)	56s
msrv (sha1)	52s
msrv (sha512)	1m 8s
msrv (ed25519)	55s
msrv (keccak)	58s
msrv (bls12381)	54s
msrv (merkle-inclusion)	32s
licenses-audits / cargo-deny (advisories, licenses, bans, ...)	41s
link-checker / linkChecker	5s
	14m 29s

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