[dataimport] introduce usage of MetadataGenerator into the massive store
This allows more flexibility and code sharing w/ nohook store.
Closes #10338621
Document: cubicweb-doc
Title: CubicWeb documentation
Author: Logilab
Abstract: Some base documentation for CubicWeb users and developpers
Section: Apps/Programming
Format: HTML
Index: /usr/share/doc/cubicweb-documentation/html/index.html
Files: /usr/share/doc/cubicweb-documentation/html/*