ROOT Board game clearing markers holder

This serves two functions:
1. It holds the clearing marker pieces for the maps.
2. Its outer dimensions are exactly the right size to sit beside the base game map and stop it from sliding side to side in the base game box.

I designed this because I was working on a [set of vase mode containers](https://www.thingiverse.com/thing:5759022) to try to store all the content from the base game and the Marauder expansion into the base game box.

The map sits on top of these containers but I wanted to ensure the slight gap along the long edge was always over the containers holding the cards, not the ones with faction pieces. This sits beside the map to ensure that gap is in the right place.

It works really well if you put all the markers in with facing the same way, then when setting up you just tip it over and they will all slide out face down.

I'm sharing this on its own because I think it has utility for a whole range of Root storage configurations which don't involve the ori