Add note about automatic inclusion in the catalog to "why use the org" pages

Such discoverability is suggested in the pages, but not explicitly stated since the catalog didn't exist then. We could also put it in the template as an example with a link to the catalog for others wishing to create something similar, then be more explicit for Imageomics.

ABC will have one at some point as well.

Read the “why use the org” pages and the template referenced in the issue, then check how catalog discoverability is currently described. Done means the pages explicitly mention automatic catalog inclusion, and the template includes it as an example with a catalog link where appropriate.

Written by the indexing model from the issue text.