Save old contract info for VDF fiber contracts for address change requests
CHANGELOG:
### Added
- [#619](https://gitlab.com/coopdevs/odoo-somconnexio/-/merge_requests/619) Save old contract PON and fiber speed in address change CRMLeads, to send them to OTRS.
Related card: https://trello.com/c/jwiEpgIj/913-camps-que-han-dapar%C3%A8ixer-al-nou-ticket-de-cu
Edited by Pelayo García