Arbitrable Dapp Migration: Governor

Migrated version of https://governor.kleros.io ([code](https://github.com/kleros/governor-snapshot)) ([config](https://github.com/kleros/governor-snapshot/blob/master/src/constants/projects.tsx))

Contract: https://github.com/kleros/kleros-v2/blob/dev/contracts/src/arbitration/KlerosGovernor.sol