Prop 204: Create Senate CW3 Group Contract

This will instantiate the CW3 Group contract for the Kujira Senate, and is responsible only for maintaining the current list of Senators. Source for this contract is available here. The contract admin is set to the chain governance module, so that only chain governance proposals may add or remove members. Once this contract is deployed, we can deploy the CW4-flex-multisig contract, configured to use this CW3 contract as its permitted voter list. That CW4 will be the one that holds the community funds, and where proposals are submitted and voted on.