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

Former-commit-id: 56d5134810aa8c867036376d38a11fe687dd0b4d
syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin