Feat/terminate contract endpoint
CHANGELOG:
### Added
- [#1135](https://git.coopdevs.org/coopdevs/som-connexio/odoo-somconnexio/-/merge_requests/1135) Add an API endpoint to terminate contracts
Related card: https://trello.com/c/mvTKjBYp/1749-nou-endpoint-per-baixa-de-contracte
Edited by Gerard Funosas