Support Arc Version Selection

[dOrgJelli]

Upon deploying your DAO, allow the user to select a specific Arc version they'd like to use, instead of just defaulting to latest.

[dOrgJelli]

This would make use of the arcVersion option shown here: https://github.com/daostack/migration/blob/29b7da1dfa2090098c8672b562a3eadc74acba90/migrate-dao.js#L4