Draft: API to recovery invoices

CHANGELOG:

### ADD
- [#1211](https://git.coopdevs.org/coopdevs/som-connexio/odoo/odoo-somconnexio/-/merge_requests/1211) Add api/invoices

Related card: https://trello.com/c/0T9n6IPB

Related merge: coopdevs/som-connexio/opencell/pyopencell!60 (merged)

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