Prior to this PR, when creating a new product.product model, a product.category
is allocated. As it is not shown on the product.expense.form view, the user
might make mistakes if he did not set the product.category himself.
This can be fixed by adding the product.category field on the view to allow
the user to modify it.
Also, some design changes are made at the same time to improve the form view.
This PR improves the product.product.expense.form view by adding the
product.category field so the user can modify it and also by modifying the
general layout of the view.
The view is modified adding the field, aligning the two first fields and
removing the notebook page for the notes and placing it in the continuity of
the view as it is the only page in the notebook
task-3413267
closesodoo/odoo#130065
Signed-off-by: Laurent Smet (las) <las@odoo.com>