v1 Absence and Attendances endpoints -Addition of 'id_v2'

For the following v1 endpoints - GET v1/company/attendances, POST v1/company/attendances, GET v1/company/time-offs, POST v1/company/time-offs and GET v1/company/time-offs/{id} and GET v1/company/time-off-types there will be an additional field in the payload named 'id_v2'.

The value of the 'id_v2' field corresponds to the UUIDs returned at the v2 Absence and Attendance endpoints and enables API users who to migrate their API consumption from the v1 to the v2 version, in a frictionless manner.