Light redesign of the extension/add-on list item.
The last time this layout was updated was in Blender 2.5, when text was
usually left-aligned, and add-ons preferences weren't streamlined yet.
The goal is to keep a familiar look, while making some improvements to
organization such as group actions (install/uninstall, buttons to external sources
like website, documentation, report a bug).
Detail images available in the pull request.
Pull Request: https://projects.blender.org/blender/blender/pulls/122726