Implements CS's recommendation for using the max(STETH-USD,ETH-USD) for redemptions only if those prices differ by 1%, otherwise take the min:
Stops out-of-gas errors in external calls to Chainlink and LST causing a shutdown. Fixed by ensuring the remaining post-call gas is > 1/64 the pre-call gas, which guarantees an OOG didn't occur ( CS-030: https://github.com/liquity/bold/issues/488)
Makes CompositePriceFeed an abstract contract (Coinspect BOLD-06)
This PR:
max(STETH-USD,ETH-USD)for redemptions only if those prices differ by 1%, otherwise take the min: