[ADD] product_kit_type: introduce kit product type with subproduct handling in Sales Orders

[piso-odoo]

Description

This PR introduces the product_kit_type module, which adds a new Kit product type to manage grouped products in Sales Orders.

Key Features

• New Product Type: Kit

  • Added is_kit option in the product form view.
  • Allows selection of subproducts when a product is defined as a kit.

• Sales Order Integration

  • When a kit product is added to a sales order, a button appears next to the product line.
  • Clicking the button opens a wizard where the user can:
    • Set quantities and prices for each subproduct
    • Confirm selection to automatically add subproduct lines to the order (readonly)
    • Update the main kit product’s price based on the values set in the wizard

• Document & Customer Portal Options

  • Sales Orders include a setting to enable or disable printing of subproduct lines.
  • The setting controls visibility in both:
    • Customer invoices
    • Customer portal order preview

[robodoo]