Code Insights: Add insight card to the standalone page

Created by: vovakulikov

Closes https://github.com/sourcegraph/sourcegraph/issues/34762

This PR adds backend and runtime insight card components (including fetching functions and card layout)

Test plan

• Make sure that all (lang stats, capture group, search-based) insights look good on the standalone insight page)

App preview:

• Web
• Storybook

Check out the client app preview documentation to learn more.