Request: add the core_nt index to related workflow tools (Kraken2, Kraken, Bracken)

Thank you all for adding the `core_nt` database index to Kraken2!!

To make the workflow flow through tools, could we please also add it to these? At the EU server would be enough but it seemed worth logging this in IDC for longer term goals too.

* Bracken?
* Kraken-filter
* Kraken taxonomic report
* Kraken-report

Requested at https://help.galaxyproject.org/t/adding-nt-core-db-to-bracken/14533/

Start by locating the reference-data definitions for the `core_nt` index and the existing entries for Kraken2, Bracken, Kraken-filter, Kraken taxonomic report, and Kraken-report. Check how the index is exposed on the EU server and confirm that the requested tools can use it; done means `core_nt` is available throughout the listed workflow.

Written by the indexing model from the issue text.