Add Fluo recipes content to the Fluo tour

The [Fluo Tour](https://fluo.apache.org/tour/) could use some content about Fluo Recipes. There is already a [recipes page](https://fluo.apache.org/tour/recipes/) at the end of the tour where it could be added.

Some topics to potentially cover:
* Combine Queue
* Export Queue

Start by locating the source for the existing Fluo Tour recipes page linked in the issue, then read the surrounding tour content for its structure and level of detail. Add coverage of the Combine Queue and Export Queue, and verify that the rendered recipes page presents the new content correctly.

Written by the indexing model from the issue text.