Add chatter to product_product

CHANGELOG:

### Added
- [#845](https://gitlab.com/coopdevs/odoo-somconnexio/-/merge_requests/845) Add chatter to `product.product` model

Related card: https://trello.com/c/DwydVdnv/1327-posar-un-chatter-en-el-model-productproduct

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