feat: Refactor auction_transaction relation

[sunce86]

Problem

With colocation, auction_id is appended to transaction call_data always (and this will also be required and verified once solvers run their own driver), so it's not needed to keep the <from, nonce> pair anymore. This paIr was used pre-colocation so that we connect the auction to the transaction hash.

Currently, our database looks like this:

settlements table (initially partially populated by EventHandler (without <from, nonce>), and later OnSettlementEventHandler updates <from, nonce>):

• block_number
• log_index
• transaction hash
• Optional from
• Optional nonce

auction_transaction table (populated by OnSettlementEventHandler):

• auction_id
• from
• nonce

Proposal:

settlements table:

• block_number
• log_index
• transaction hash
• Option<auction_id>

Drop auction_transaction table.

EventHandler would insert settlement on each new event, while OnSettlementEventHandler would fetch all settlements without auction_id and populate that field and all depending data (settlement observations and order executions). This would make OnSettlementEventHandler completely reorg friendly since right now the auction_transaction table is not reorg friendly and does not contain column block_number which would allow entry deletion when EventHandler detects reorg.

Related to #2275

[MartinquaXD]

Seems good to me. I don't see any obvious problems with this approach and always found that we had to join using from and nonce instead of auction_id clunky.

[fleupold]

Sounds good to me! If we make a new version of the contract, we will likely make auction ID a mandatory part of the calldata anyways.

[sunce86]

Done with #2283