Feat/relayer refactor

[SoraSuegami]

It has the following changes:

1. Update the utils package.
   I added some functions exposed for nodejs to the utils packages, renamed AccountKey and WalletSalt to AccountCode and AccountSalt, and moved the generate_email_auth_input function from the relayer to utils package.
2. Update the circuits package.
   I modified the scripts and tests (not circom circuits) in the circuits package to follow the above updates. I ensured that the circuits tests passed using the generate_email_auth_input function.
3. Update the relayer package.
   I modified the relayer rust codes to follow the above updates. Specifically, I renamed account_key to account_code.