Make it possible to share link with only the Search API Key

[Kerollmops]

Sharing a link to a mini-dashboard webpage with other users would be great without leaking the primary API Key. The main reason why we need the primary API Key is because the dashboard requests the list of available indexes.

However, by sharing the index name in the URL with a query parameter alongside the Search API Key (or even a tenant token), the dashboard no longer needs to list the indexes by only showing the index name and avoiding displaying the number of documents.