Use client with extraFee instead of readOnlyFee. Rename
NewNoFeeBalanceClient to NewBalanceClient since no-fee client is no longer
used.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Calculate payments to storage nodes for the passed audit when changing the
epoch. The calculation results are wrapped in a call to the Balance contract
(one transaction per user-to-user transfer).
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
