feat(core): add `rowHighlightCssClass` & `highlightRow()` to SlickGrid

[ghiscoding]

• this new approach is much simpler than using ItemMetadata and calling multiple updateItem() and render() and is a lot more performant
• also fix potential mem leaks found on some setTimeout not having any clearTimeout assigned which could cause potential mem leaks
• note that is only a temporary highlight and will also disappear as soon as soon as we call any of: scroll, render, invalidate