Added ticket_number to Contract api, model and view
CHANGELOG:
### ADDED
[#365](https://gitlab.com/coopdevs/odoo-somconnexio/-/merge_requests/365) Added OTRS ticket\_number to Contract api, model and form view
Edited by Pelayo García
CHANGELOG:
### ADDED
[#365](https://gitlab.com/coopdevs/odoo-somconnexio/-/merge_requests/365) Added OTRS ticket\_number to Contract api, model and form view