Implement Retirement Aggregator Fee Split

[0xAurelius]

KIP-33 has passed. The RA fee handling logic should have configurable parameters to control the splitting logic for the convenience fee

• daoFeeShare: indicates what proportion (e.g. 0.8 for 80%) goes to the DAO wallet. Remaining fee goes to the treasury.
• daoWallet: address where the DAO's share should be sent

We may eventually want to generalize this to support referral fees, but we'll treat that as a future piece of work