All custom price overrides

Every price EVE-KILL applies on top of market data, in one unpaginated response. Market history is unusable for items that rarely or never trade — titans, faction capitals, officer modules — so killmail values use these overrides where they exist. valid_until is the last date an override applies to; open-ended ones carry the 9999-12-31 sentinel, and a type may have several rows if its override changed over time.