[Doc] Add ra-data-graphql-supabase to data provider list

[maxschridde1494]

I recently decided to test out supabase for a quick microservice my team was spinning out. We use react-admin for a lot of custom dashboards so I decided to run with vite, react-admin and cloudflare pages on the front end. The combo of supabase and react-admin proved to be powerful--fast, flexible, robust. I also wanted to try out the auto generated supabase GQL interface (via pg_graphql). I noticed there is a REST supabase dataprovider in ra-supabase, but couldn't find a GQL dataprovider so I went ahead and wrote one (repo here).

• The PR targets master for a bugfix, or next for a feature
• The PR includes unit tests (if not possible, describe why)
• The documentation is up to date

[fzaninotto]

Thanks!