[IMP][18.0] partner_import_helper: xlsx template, wizard, multi-company and tags

[arnaudlayec]

Hello,

UPDATE 2025-12-11: also add improvements on product_import_helper and move shared methods to base_import_helper

In short: this PR adds an XLSX template in partner_import_helper and product_import_helper that is ready to use from a wizard accessible in Settings/Technical menu.
The methods that read the template and load its data are designed to be inheritable.
The XLSX template itself is designed to be self-supportive, with a Tutorial sheet (ignored during import) for integrators and possibly customers.

In base_import_helper:

• add a a menu "Import Helper" in Settings/Technical, that can be used by other import module
• the template download action
• the XLSX import/read logic methods. It call methods to be defined in [partner|product]_import_helper, which use a vals_list var corresponding to the Excel sheets
• button and fields to the existing wizard, formerly only used for report of the import
• a "AI Engine" selection field in the wizard
• openpyxl dependency

In partner_import_helper:

• XLSX template in data file with 3 sheets:
  • companies: to add companies, 1 bank account per company (optional), 1 invoice address (optional), 1 delivery address (optional)
  • contacts: to add other contacts in companies, using the type freely. It can also add non-company related contacts (1st level)
  • banks: to add other bank accounts to companies
• add support of multi-company (fake company_ref field in vals) and tags (fake categories field)

In product_import_helper :

• support of product tags
• support of a supplier_code magic field, keeping support of supplier_id
• the XLSX template has only 1 interpreted sheet products. It has a 2nd sheets (+Tutorial) which is not interpreted, the supplierinfo, which only is the template to use to import them from the menu "Purchase > Configuration > Vendor price list"

[metaminux]

Globally, I think the code is running without error

I really think the use of ChatGPT should be an option.
We need to make a choice here...
Mine would be to add a selection field on the wizard to use it or not (and in the future use other engines)

I also think providing the XLSX file as a template should be accessible from the UI.
Hosting the file in the "static" directory and making a button that returns an "ir.actions.act_url" should do that...

[arnaudlayec]

Hello @metaminux, thank you for your review
I think those were great feedbacks, it's been updated in the new commits