Stateless: Add multiproof function and use when building witnesses

[bhartnett]

This PR adds a multiproof function to the aristo proofs module which returns all the proof trie nodes for an entire block (account and storage trie nodes) together in a single list. Doing so enables sharing the node cache with all the account proof and storage proof calls in order to further improve performance.

By using the table parameter which maps account paths (address hash) to a list of storage paths (slot hashes), when building the witness, only a single loop through is needed (linear time with respect to the number of witness keys) instead of a double loop (quadratic time) which results in rather bad performance when building the witnesses during the DOS block ranges where some blocks generate more than 50K witness keys.