Art document doesn't include any visual examples + perspective update

[K-Dynamic]

Opening this issue as someone resprited a vending machine, only to be told that the style they should've followed required searching hundreds of messages on Discord from last year. There's also the fact people are told to look at 'sovl' or 'r4407' sprites and avoid 'eris' sprites, which are kinda hard to reference behind tons of commits on various codebases.

Using images will also help cut down the word count on the document. They'll also help act as quick references on which sprites to follow and not to follow.

Some items are being resprited to cabinet perspective, which should also be updated in the document.

Example sprites to use:

• APCs and substations