Code Insights: Re-implement (copying) code insights example code insights layout for about.sourcegraph.com page

Created by: vovakulikov

Related issue https://github.com/sourcegraph/customer/issues/632

Backfround

For the marketing landig page we should re-use our in-product landing page components. To be more specific we should use insight examples layouts. The main goal of this issue is moving (essentionally just copy pasting) code insights exmaple section charts/layouts to the about.sourcegraph.com repo.