[all] Investigate how to reduce/amortize gas costs

[ArjunBhuptani]

Gas costs are insane. We need to figure out how to reduce them to make running a router on Ethereum economical (L2<>L2 routers are totally ok). General strategy for this:

1. Analyze primary drivers for gas costs in the current system. Figure out what the minimum possible cost is.
2. Model upfront onboarding costs, ongoing operating costs, and potential fee revenue.
3. Look into batching up onchain txs via zkps.