Enhancement Request: "Federated search" - Indexing and search across multiple Docusaurus builds

[rautio]

We use Docusaurus internally across several repos, but there is no easy way to search across all of them today. I would love a way to generate indexes from multiple Docusaurus builds and combine them into a single search functionality. I want to create a Docs Hub that links to the many different docs sites and creates a "federated search" across all of them.

If something like this already exists, that would be awesome; please let me know.