Feat: Workshop Plywood Storage Cart 🛒

At present the "materials" (fresh plywood + useful offcuts) section of the workshop is mess:


This is an eyesore. Collects dust. Takes time to find a piece of material I can use. And ultimately it's _dangerous_. ⚠️
I'm not "proud" of this. in fact it bugs me a _lot_ each time I walk into the workshop.
I've been meaning to "fix" it for _months_. But it's not a "project" that has a practical purpose in the house.
But having a well-organised and _safe_ workshop is a [***`system`***](https://github.com/dwyl/home/issues/113)

My Goal is to use only "scrap" material for this, but I suspect I may need to use some fresh materials ...

# Todo

+ [x] Measure how big the Cart should be. I'm thinking `~400 x 1220` on the base. 📏
+ [x] Find materials in the stack that can be used to make the cart. 🔍
+ [ ] Wing it. 👷