use subsidy value from config, instead of hardcoded value, to facilitate easy changing during testing
and latest nightly clippy raises a lint on using Arc<Relay> as a key in HashSet -- this repo would not touch this key mutably but there is no way to signal that to the type system, so for now, refactor to working over indices into Auctioneer::relay vec
Arc<Relay>as a key inHashSet-- this repo would not touch this key mutably but there is no way to signal that to the type system, so for now, refactor to working over indices intoAuctioneer::relayvec