This update lets Odoo intentionally reuse the same many-to-many relationship for multiple fields on a model, making it easier to show the same related records in different filtered views. It also adjusts internal handling so these shared relationships work correctly when data is linked back from the other side.

This allows a model to have several fields using the same relation on purpose,
for instance to show the related items filtered by domains.

Also adapt the code to handle multiple many2many inverses.