[Suggestion] Allow NOREX trading boss vestiges

So, the NOREX black market trader doesn't currently include the boss vestiges. I propose allowing trading of *GH boss vestiges* for each other, at something like 2 to 1. So if you're on Styx, you could trade two of the Garganutan Prime vestiges for one Unstable Quarrite or one Rimetusk Matriarch (and similar on the other maps), but only if you have the flag for the target vestige (would have to have the Unstable Quarrite flag already in the example trade).

Maybe allow the non-GH boss vestiges in a similar way, so you could trade 3-5 sandworm vestiges for a black wolf vestige.