Conceptualise partial swapping

[valiafetisov]

Goal

A developer is able to implement the desired feature.

Context

Currently, we only allow partial bidding on collateral auctions when participating with your own DAI. But it's also possible to do so with swap-like transaction using callee. The only technical problem (and the advantage for the user) is that every time the bid amount is changed, the market unit prices will also change (and we might also need to refetch them in order to display correct numbers).

Note:

• This feature was first time proposed in Support multiple ways to swap collaterals #229
• This feature was mocked in Mock partial swapping #528

Assets

Latest mock: https://whimsical.com/makerdao-new-collateral-BT3LASEF2aRAQEuav79UUw

Requirements

• The proposal for the first iteration of this feature is to limit swap amount choices to a few predefined "probes" per market (but in the future we want to provide user with the regular input)
• UI-wise we want to show those options in a table, so the user can full overview of all "probed" prices and can choose other markets/amounts
  • the same component should be used to show those numbers inside Market unit price expandable block as well as in the Amount to swap expandable (with same tooltips, but with different main values: marketUnitPrice vs netTransactionProfit)
• The bot will need to have not just suggestedMarketId, but also suggested swap amount

Tasks

• Conceptualise implementation/refactoring
  • Outline what needs to be done
  • Outline new vs old data structures
  • Outline new bot behaviour
  • Propose roadmap, ie issue(s) to get there