Feat: A4 Paper Tray from 5mm Plywood

Problem: we have _lots_ of paper around the office that needs to be sorted, organised and processed. We don't have enough trays for _temporarily_ storing it all ...
We could _buy_ those trays from IKEA, Staples, etc. but where's the fun in that? 😜
If we make our and _learn_ from the process, we could:
a. make something _cheaper_ than the mass-produced stuff
b. make a _better_ design that meets our specific needs
c. make _dozens_ or even _hundreds_ of them for ourselves and others

# Todo

+ [x] Create a prototype A4 Paper In-tray design
+ [x] Should fit a flat A4 sheet of paper with 5mm spare on all sides
+ [x] Should use **`5mm`** birch plywood (which we know works well on our Laser cutter)
+ [x] Should have interlocking joints for easy assembly
+ [x] Laser Cut the V1 prototype
+ [x] Assemble (glue) the prototype
+ [x] UX-test it!