feat: Add HL AI SDK provider

Adds new directory with AI SDK provider package, implemented mainly with
Mistral/Groq as references. Most custom providers appear to publish their
packages as namespaced or separate packages rather than in an SDK. We
could consider doing the same.

A few TODOs where I'm unsure about the API responses and don't have good
enough WiFi connection on the plane to test

Author: jamesbaskerville

integrations/ai-sdk/CHANGELOG.md

@@ -0,0 +1 @@
+CHANGELOG