Feat/terminate reasons endpoint

CHANGELOG:

### ADDED
- [#1150](https://git.coopdevs.org/coopdevs/som-connexio/odoo-somconnexio/-/merge_requests/1150) Created terminate reasons endpoint

Related card: https://trello.com/c/HvbHJQYL/1759-endpoint-motius-de-finalitzaci%C3%B3

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