feat: derive `Clone` for `StarkProof` #257

Job	Run time
build	22s
verify-proofs-stone5-keccak-160-lsb (dex)	1m 5s
no-std-build (dynamic, blake2s_248_lsb, stone5, armebv7r-none-eabi)	1m 59s
verify-proofs-stone5-keccak-160-lsb (recursive)	1m 7s
no-std-build (dynamic, blake2s_248_lsb, stone5, riscv64imac-unknown-none-elf)	1m 27s
verify-proofs-stone6-blake2s-248-lsb (dex)	1m 3s
verify-proofs-stone5-keccak-160-lsb (recursive_with_poseidon)	58s
verify-proofs-stone6-blake2s-248-lsb (dynamic)	1m 11s
no-std-build (dynamic, blake2s_248_lsb, stone5, aarch64-unknown-none-softfloat)	1m 32s
verify-proofs-stone5-keccak-160-lsb (small)	59s
verify-proofs-stone6-blake2s-248-lsb (recursive)	58s
no-std-build (dynamic, blake2s_248_lsb, stone5, aarch64-unknown-none)	1m 20s
verify-proofs-stone5-keccak-160-lsb (starknet)	1m 7s
verify-proofs-stone6-blake2s-248-lsb (recursive_with_poseidon)	58s
verify-proofs-stone5-keccak-160-lsb (starknet_with_keccak)	1m 22s
verify-proofs-stone6-blake2s-248-lsb (small)	1m 7s
verify-proofs-stone6-blake2s-248-lsb (starknet)	1m 20s
verify-proofs-stone6-blake2s-248-lsb (starknet_with_keccak)	1m 26s
	21m 21s

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