`no_std` support #103

Job	Run time
build	35s
verify-proof (dex)	1m 2s
Test no_std support (dex)	2s
verify-proof (recursive)	57s
Test no_std support (recursive)	5s
Test no_std support (recursive_with_poseidon)	3s
verify-proof (recursive_with_poseidon)	1m 10s
Test no_std support (small)	3s
verify-proof (small)	1m 12s
Test no_std support (starknet)	3s
verify-proof (starknet)	1m 9s
Test no_std support (starknet_with_keccak)	2s
verify-proof (starknet_with_keccak)	58s
	7m 21s

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