Update the motoko implementation

[ccyanxyz]

Need to update the motoko implementation:

1. CAP integration
2. ok -> Ok, err -> Err
3. More error types

[ccyanxyz]

public type TxReceipt = {
    #Ok: Nat;
    #Err: {
         #InsufficientAllowance;
         #InsufficientBalance;
         #ErrorOperationStyle;
         #Unauthorized;
         #LedgerTrap;
         #ErrorTo;
         #Other;
         #BlockUsed;
         #AmountTooSmall;
    };
};