implement bls12-381 functions #4314

Job	Run time
build-fuzz	5m 4s
check-git-rev-deps	9s
cargo-deny (advisories)	43s
build-and-test (msrv, ubuntu-latest, x86_64-unknown-linux-gnu)	13m 40s
cargo-deny (bans licenses sources)	44s
docs	6m 4s
build-and-test (msrv, ubuntu-latest, aarch64-unknown-linux-gnu, true)	8m 47s
fmt	7s
build-and-test (msrv, windows-latest, x86_64-pc-windows-msvc)	21m 16s
build-and-test (latest, ubuntu-latest, x86_64-unknown-linux-gnu)	13m 29s
publish-dry-run	0s
readme	3m 14s
semver-checks	5m 52s
build-and-test (latest, ubuntu-latest, aarch64-unknown-linux-gnu, true)	8m 17s
build-and-test (latest, windows-latest, x86_64-pc-windows-msvc)	19m 19s
complete	1s
	1h 46m 46s

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