Enable Staking Rewards

A portion of BLD sold in the public sale in December 2021 will unlock at the start of July. Ahead of BLD unlock, staking rewards should be turned on to ensure network operation. BLD stakers also receive rewards in IST based on fees earned by the protocol. Over time, IST fees may become the primary reward for BLD stakers. However, as these fees will grow with the Inter Protocol, it will take time for them to become sufficient to operate the network on their own. Therefore, BLD issuance will be used for rewards until that time. BLD issuance should be managed by governance to not overspend, and therefore should be set conservatively and increased as needed. Additionally, this proposal will adjust several other key parameters regarding chain operation and governance to prepare for the launch of Mainnet 1. See also https://commonwealth.im/agoric/discussion/5797-staking-rewards-and-genesis-parameter-updates