DnD shakeable miniature box inserts

remix from stackable miniature box.
these remixed boxes have a grove at the bottom. this allows you to put in a insert for the amount and size of mini's that you have. and makes the bottom changeable without reprinting the whole box.

the insert_full_box_slids file is my latest insert inspired by `D&D Miniature Figurine box for Heroforge models`
i use ieces of foamy draft strip that go in the slids to push the minis up against the rail. this keeps the minis in place during transport!