feat(DI-1787): update quickstart and api integration

[aotella]

This commit updates the documentation for the Insights product to align with the new v3 API. The quickstart and API integration guides have been overhauled to reflect the new endpoints and workflow.

Key changes:

• API endpoints have been updated to v3. This includes:
  • POST /v3/fiData (from /v2/fiData)
  • POST /v3/insight (from /v2/insight)
  • GET /v3/insight (from /v1/insight)
  • POST /v3/template (from /v2/template)
  • POST /v3/purge (from /v2/purge)
• The insight generation process is now documented as a two-step asynchronous flow: first triggering the generation, then polling for the result.
• All request and response examples have been updated to match the v3 API schemas.
• The description of refId and the data ingestion process have been clarified.

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Add a new API reference page

Checklist

• Create a .json file with the product path as its name
• Create an api-reference.mdx file in the respective product folder inside content folder
• Add frontmatter with all the metadata
• Review the order of items in Sidebar using the Sidebar preview option
• Add API reference in JSON format (OpenAPI or Swagger) into created .json file.
• Used the Content preview portal to view changes
• Once all changes are done, update the menu items by using the Menu Items option