[IMP+FIX] intrastat_product: Several things:

* Add product_origin_country_id on declaration/computation lines

  Copy incoterms and destination country from SO to invoice when invoicing from SO
  We need weight even when supplementary units is used
  Small cleanups and enhancements

* Add support for accessory costs

  Add default values for intrastat transaction on company
  Code cleanup

* If rounded weight is 0, put 1

  Take into account the taxes for B2C
  Small code cleanup

* Remove field exclude_from_intrastat

  Re-organise view of intrastat.product.declaration

* Add option intrastat_accessory_costs on company

  Set more fields as invisible (localisation should put them visible if they need it)
  Fix handling of suppl. units when hs_code is empty on invoice line (but set on product)
  Small usability enhancements

* Include selection of type of invoice in search, for better perf

  Isolate domain in a _prepare method, for easier inheritance
  WARNING: I changed the default selection of invoice type ; adapt it in your localization m
  odule if necessary
  Add intrastat_transaction_in_refund for company (not needed for France, but may be needed elsewhere)
  Add a log when an invoice line is skipped

* Include product code in warning msg on weight

* Inspired by the PR https://github.com/akretion/account-financial-reporting/pull/8 of Luc de Meyer

intrastat_product/models/hs_code.py

@@ -1,4 +1,4 @@
-# -*- encoding: utf-8 -*-
+# -*- coding: utf-8 -*-
 ##############################################################################
 #
 #    Intrastat Product module for Odoo