Create cookbook with example of use case Chat + tools

[mrm1001]

Motivation: In order to have a soft launch of this new (and unique) feature of Haystack, it would help to have some end-to-end example other than the feature usage example that will be in the docs.

Description:

• We already have a tutorial that uses chat with tools. We could change this tutorial to showcase how to use OpenAPI tools.

Outcome:

• Should use OpenAPI tool to showcase it in a end-to-end use case.