[Documentation] New "Model provider integrations" pages

Hi all!

We are very excited to share these new “model provider integrations” pages.

They will provide a more user-centric view of Weaviate’s integrations with many amazing model providers.

Currently we have the API-based integration pages up, and we will be adding pages for self-hosted integrations shortly as well.

Please let us know what you think, and report any bugs here.

JP & the docs team.