Hartwig Piece Set

This was requested by @bendunkle at https://lichess.org/forum/lichess-feedback/any-interest-in-adding-a-hartwig-piece-set My solution is posted at: https://userstyles.org/styles/178667/hartwig-set-for-lichess-org Piece images provided by @bendunkle

I used the images provided by bendunkle in the request thread, I'll add the credit