BOARD: add scraper shell app for boxart

[Apaczer]

based of Onion's BoxArt scraper, but purely for wget Libretro database with lot of a cleanup, plus to work of our /roms curent dir tree structure.

TODO:

• add optional resizing option to max 128px=width (& ~170px=h) via pngquant for reducing space and smth that handels px size change.
• Arcade non-merged ROMsets can't be d/l since we rely on Non-intro/Tosec naming when fetching images