SFP/SFP+ box, customizable

I liked the original, but wanted to make sure that it would be a nice and tight fit, so I have been reading the SFP MSA and measuring my SFPs to make a it a good fit with as tightly packed modules as possible.

The slots have gotten identifiers (1A, 1B.. 5D) and a paper slot so that it's possible to write on the front what the contents are, so that you can see what's in the box without removing each module.

## Changes:

- Added 0.3mm printer clearance
- Correct QSFP width


## TODO:

- Should add some round feet at the bottom and some corners on the lid to make them stackable
- Split SFP / QSFP version
- SFP-DD/QSFP-DD versions (deeper)

## Recent changes

- QSFP version! Have not personally tested it yet.
- 14 -> 16mm spacing between the SFPs so that the GLC-Ts should fit (head height / y dimension looking from the front)