ballot/v0 package

Package ballot is a Gno port of the classic Solidity "Ballot" voting contract from the Solidity docs. A chairperson seeds a fixed list of proposals and grants specific addresses the right to vote; each voter can either cast a direct vote or delegate their weight to another voter, and delegation follows a chain so a delegate who later delegates further still carries every accumulated weight. The winning proposal is whichever has the most accumulated weight at query time.