## Add: Board for Vellemann K8200 (derived from 3Drag)
* Boards.h: updated comment for board 3Drag - K8200 removed
* Boards.h: added `BOARD_K8200` with ID 78
* language.h.: machine name and firmware URL for new board
* pins.h: added `K8200` to any `#if` with `3Drag` and corresponding
comments