Signature

[boterop]

ℹ️ This issue is part of Epic #58

Objective

Create a helper to build checks and attach signatures and signers into the code and request.

Checklist

• attach: Receives a CommandPayloadStringifiedJSON and a list of keysets, signs the payload with each keyset from the list and returns a list of SignatureWithHash
• pull: Turns a SignatureWithHash into a Signature
• pull_signer: Extracts the pub_key from the keypair and inserts it into the signer
• check_hash: Validates if a hash is valid for that command