Improved Priority bidding strategy

[codyborn]

This PR attempts to solve the trade-off between bid durability and maximizing pi for the swapper.

Runs multiple bidding strategies in parallel:

• Always min bid based on gas price (multiplied by some buffer)
• Create fallback bids based on the order size and bid_bps.

The min bid is based purely on the gas cost and is intended to be on-par with Classic. However, this bid will break if the route changes at all against the swapper. Therefore, we send a minimum of 3 fallback bids for each order. For large trades, it's worth it to submit multiple bids for a given order. The number of fallback bids is proportional to log10 of the quote amount. Each order of magnitude increase above 1 ETH, increases the number of fallback bids by 1.

Number of bids calculation

To be precise, we first estimate the quote in terms of gwei (using the gas in wei and gas in quote). We then take the log10(quote_in_gwei) and subtract 8 to get the number of fallbacks (anything less than 1 ETH gets only 3 fallbacks).

Bid amount calculation

The bid amounts start from the 100% and work their way down. The jumps in spread is exponential increasing amounts of volatility.
The bid amount follows the formula: f(x) = min_bid - (BID_SCALE_FACTOR * 2^x)
where f(x) is the bid amount and x is the bid number.

To make this concrete, let's assume the following:

• BID_SCALE_FACTOR: 50
• min_bid = 10,000 (100.00%)
• quote_in_gwei = 1.01 ETH

The quote_in_gwei is 1010000000. This is 1.01E9 gwei so the log10 result is 9. We subtract 8 from 9 to get 1 (the number of additional fallback bids to add to the 3 default ones). This tells us to create 4 fallback bids:

1. 10000 - (50 * 2^0) = 9950
2. 10000 - (50 * 2^1) = 9900
3. 10000 - (50 * 2^2) = 9800
4. 10000 - (50 * 2^3) = 9600

⚠️ Note that this PR introduces a new CLI for Priority Orders, min_block_percentage_buffer which can be used to adjust the tx submission time (defaults to 100).

EXACT_OUTPUT

This PR also adds EXACT_OUTPUT to Artemis for all order types.