Add "Create AI Agents on Snowflake with Lang AI" samples

[fjaguero]

This PR adds the samples for the guide called "Create AI Agents on Snowflake with Lang AI" (Quickstart PR here)

Lang.ai Native Snowflake application provides AI Agents for product managers that leverage your existing Snowflake data (unstructured and structured data) to serve meaningful product recommendations —with context— directly in Slack.