cli: create GetWalletBalances() to fetch multiwallet balances
cli: create GetWalletBalances() to fetch multiwallet balances

Former-commit-id: 12639e066de2d10f12f6426fe13df52c0bf85bc1
syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin