When rating with the smiley mecanism, the rating value will be 1,
3 or 7. The rating model allow value in range [0, 10]. When using
the star mecanism, usually, only 5 stars are used to introduced a
rating. This will set a rating value in the range [0, 5], which
is not aligned with the range of the model, nor the smiley range.
Purpose of this commit is to uniformize the range of rating, so if a
model is using both mecanism, the average will be correct. Solving
this problem implies to apply a conversion factor between the
database value and the displayed one.
Migration:
As only product.template was using star mecanism in odoo community,
a migration step should be applied to multiply of ratings of
product.template by 2.
Task-1941432
closesodoo/odoo#31141
jem-odoo
98052fb51c