Improve random sector abandoned stations handling

[jaghaimo]

I don't keep a list anywhere, might have to check all entities in the sector once they can be identified by their memory key at least (set by Misc.setAbandonedStationMarket)

    public static void setAbandonedStationMarket(String marketId, SectorEntityToken station) {
        station.getMemoryWithoutUpdate().set("$abandonedStation", true);