`no_std` support #108

Job	Run time
build	3m 56s
Test no_std support (dex)	1m 34s
verify-proof (dex)	1m 15s
Test no_std support (recursive)	1m 39s
verify-proof (recursive)	1m 14s
Test no_std support (recursive_with_poseidon)	1m 39s
verify-proof (recursive_with_poseidon)	1m 4s
Test no_std support (small)	1m 35s
verify-proof (small)	1m 6s
Test no_std support (starknet)	1m 38s
verify-proof (starknet)	1m 6s
Test no_std support (starknet_with_keccak)	1m 35s
verify-proof (starknet_with_keccak)	3m 18s
	22m 39s

Provide feedback