If you’re interested, the most up-to-date tutorial I’ve found is here: Unreal Engine 4 Rendering Part 6: Adding a new Shading Model | by Matt Hoffman | Medium
Unfortunately it requires modifying the engine source and a decent understanding of shader programming, and I’d imagine you’d have to force the engine to use forward rendering to get the per-vertex lighting you’re looking for (deferred rendering can only do per-pixel lighting).