Add Skill Gems to the Reforging Bench

Just a QOL I noticed during one of my play throughs.

I have collected a lot of tier 12 skill gems, but very few tier 13.

It would be nice to be able to convert 3 of the uncut skill gems for 1 a tier higher. Same for uncut spirit gems.

It won't affect much for the initial play through, but as players create more characters, it will help out.

Upgrading and downgrading gems should be a thing till lvl 18, if they add it. 19 is raining like crazy, 20 should be hard to get. 21 should be nearly impossible to get and that is fine. Not that I like burning prisms and PJOs, but... Top godhood stuff should be extremely rare and that is fine.