Log 3 click events for new features on Search Homepage and Repo Page

Created by: poojaj-tech

Feature request description

Add logging to measure usefulness of new features added to Search Home Page and Repo Group Page

1. Homepage (Done) Repogroups section: click + repogroup title + search link (New) Example Searches list section: Item click + search link (New) Search a language list section: Item click + search link
2. Repogroup (Done) Search Examples -> Search button: click + search link (New) Repositories List: click + repo link

Once we add this data, we can also segment users by new feature usage for other analytics like retention and # of searches. See Search Homepage Data (1. Usage) for more details.