Expose Meilisearch's geo-based search

See here for more information: https://docs.meilisearch.com/learn/advanced/geosearch.html

This could possibly be exposed with `Filter` and `SortBy` types, but I haven't looked into it enough to know for sure.

I personally don't have a need for this in my app which is why I didn't implement it, but if someone did need geosearch in their app, I would be happy to review a PR.