cubicweb #3390012 The tutorial on the massive data import is not accessible via an URL [validation pending]

The tutorial on the massive data import is at cubicweb/doc/tutorials/dataimport, whereas the other tutorials, accessible via an URL, are at /cubicweb/doc/book/en/tutorials, hence the massive data import tutorial is not exposed via an URL. It should be.

priorityminor
typebug
done in3.21.0
load left0.000
closed by#d1164ba9ac23 [doc] put the tutorials between the intro and the `Repository development` toc of the book