feat: Allow iterative settlement of batch auctions

[Oighty]

Goal of settlement: Process sorted bids to find marginal clearing price of batch auction.

Problem: The EVM limits the number of bids we can process in a single transaction due to the gas limit. Therefore, auctions that require more bids to settle than can be processed are bricked.

Solution: Allow auction to be settled over multiple transactions if needed.

The implementation of these changes is fairly minimal; however, testing all of the edge cases will require quite a bit of work. I made the following changes:

• _getLotMarginalPrice is the function within EMP that iterates through bids to find the marginal price. Most of the changes are focused here.
  • Accepts a num_ parameter for the number of bids to iterate through (passed through higher-level functions that call it). The loop now iterates over num_ or numBids still in queue, whichever is smaller.
  • Changed the loop to only trigger the "last bid" result block if the last bid being iterated over is actually the last bid in the array.
  • Added a finished variable to MarginalPriceResult which is set whenever one of the result blocks are hit. An important thing to note is that, unlike the decrypt process, settlement can end without hitting the end of the queue. Therefore, this can be set in multiple places where we previously exited the loop.
  • In order to pick up where we left off on a second settle transaction, we need to store the intermediate result. To do so, we store the total processedAmountIn from previous calls and the lastPrice seen in a new mapping: _lotSettlement
• _settle uses the result of _getLotMarginalPrice to determine what to do next.
  • If result.finished is true, it behaves as before. This includes updating the auction status, emitting an event, and calculating the totalIn and totalOut values to provide to the AuctionHouse.
  • If result.finished is false, it skips the previous behavior and stores the partial results for use on the next call. It specifically does not update the status of the auction so that the function can be called again.

Tasks

• [x] Implement iterative settlement
• [x] Update existing tests to compile/run
• [x] Add new tests to cover the potential states of partially settled auctions.
  • [x] Standard, multi-step settlement
  • [x] Auction settles between last bid of previous settle call and first bid of next one.
  • [x] First bid on second settle call is a partial fill.

[Oighty]

@0xJem let me know what you think of this version for iterative settlement. It's less invasive than I expected.

[0xJem]

First bid on second settle call is below minPrice

This isn't possible, actually. It will be filtered out in the decryption stage.

[0xJem]

Update callback test salts (think there may be a fix to port over from the other branch?)

I haven't seen any failures

Implement minBidSize -> quoteToken feature on this branch?

Let's clarify what's required

[Oighty]

I haven't seen any failures

I had to clear the bytecode on my end. Disregard

Implement minBidSize -> quoteToken feature on this branch?

Let's clarify what's required

Going to do this on a separate branch.

[0xJem]

Good to merge?

[0xJem]

I changed the base to develop, since we will have a couple of PRs merging in and don't think we should be leaving master in a potentially broken state.