Lean Consensus Spec Tests

Test vectors for the Ethereum Lean Consensus Spec.

Test Vectors

devnet2/ - 43 test vectors from commit 92d044f (fork_choice, state_transition, verify_signatures)
devnet3/ - 58 test vectors from commit ... (fork_choice, ssz, state_transition, verify_signatures)
consensus/ - devnet5 prod-scheme fixtures generated from leanSpec commit e8014f9c5f384f7593e4ca819c0ba422a7754754 with locally generated prod keys in keys/prod_scheme/.