CLI bugfixes and improvements

[n13]

• better help on the commands
• multisig --expiry is optional, filled in with delta of 2 hours
• remove buggy "expected" address from msig creation
• Fix hash for predicted msig account
• Fix preimage hash (to blake2)
• Changed referenda voting to this, so the vote aye or nay is clear (before nay is just omit --aye)
  quantus tech-collective vote --referendum-index 0 --vote aye --from s3