Solver accounting restructuring

[fhenneke]

It might be required to change the structure of solver rewards in the short to midterm. The goal would be to make it easier to understand the components of solver accounting, make it easier to debug problems, and inform design decisions for the accounting in the long term.

A design I currently have in mind would split the solver payments into three parts

• solver rewards for batches (and quotes); paid to solvers
• protocol and partner fees; paid by solvers to the protocol and by the protocol to partners
• buffer accounting; paid by the protocol to solvers

Data for each component is computed separately. Data is optionally combined when generating transfers from the data.

In pseudo code, it could look as follows

def propose_payments()
    rewards = compute_rewards()
    protocol_fees = compute_protocol_and_partner_fees()
    buffer_accounting = compute_buffer_accounting()

    payments = merge_data(rewards, protocol_fees, buffer_accounting)

    transfers = generate_transfers(payments)

    post_transfers(transfers)

Data fetchers and configs could be passed explicitly to those functions. Since different steps are more self-contained, it should be easier to test and to debug errors.

This design would make it easy to, e.g., skip calling a slippage query for buffer accounting when computing payments on Gnosis. Or to stop merging negative slippage with positive rewards.