Add missing images to box model lesson

[jdwilkin4]

Here is the lesson

https://www.freecodecamp.org/learn/full-stack-developer/lecture-working-with-css-transforms-overflow-and-filters/what-is-the-css-box-model

The original hashnode script had a whole bunch of images which enhanced the lesson. So those needed to be added in by one of the curriculum team members. Once that is approved, the lesson can then be updated.