Create common package. Define Ballot struct in common package. Use new type
in all contracts with ballots.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Remove old ballots first so there won't be any
interference with votes of the same tx in the
future after `blockDiff` blocks.
Signed-off-by: Alex Vanin <alexey@nspcc.ru>
Sidechain contracts include alphabet contracts for governance
and audit, balance, container, neofsid, netmap, reputation
contracts.
Signed-off-by: Alex Vanin <alexey@nspcc.ru>