Add link on type page to the external entity data list

I fixed the link.

For consideration, there is a list link in the dropdown, but edit is shown by default. Maybe this should be the first link instead?

Another option is to link the external entity type label.

That makes me think I was wondering if the way we assign routes could not be problematic. I forgot what I did bu I think if you use the Drupal contact form and then create an external entity called "contact", you don't have access to the contact page anymore. To be checked (I postponed that task and forgot about it). Maybe we should handle XNTT routes differently? For instance, provide a default route based on the type, like now, but allow user override on the XNTT type form? Or should forbid the use of existing routes as XNTT type machine name? There is also this recurrent problem of XNTT with underscore in their machine name that is translated as dashes in URLs (while underscores are leagal in URLs but not following standards).

Maybe treat that path as an alias, with a config form setting that checks if it's an existing route on save?

Commit # 60bbb626 provide major improvement: it is now possible to manage conflicting routes and choose custom routes different from the external entity type identifier.