Be able to provide relative icon path

Problem/Motivation

This is a follow-up of a discussion in 💬 Be able to provide icons to patterns used as layouts Fixed .

icon_path is working but it should be path relative to the Drupal installation:

 icon_path: "themes/custom/ui_suite_bootstrap/screenshot.png"

So hard to provide icons in contrib modules/themes.

Proposed resolution

Would it be possible to make it relative to the module/theme providing the pattern or relative to the pattern itself?

What to do in the case of pattern override?

Remaining tasks

Discuss on the solution
Implement it