Assign IPv6 to router-001

Summary:
Use native IPv6 from OVH, with similar configuration than for web-001.

Works now router-001 has been upgraded to FreeBSD 13.2.

NetBox: https://netbox.nasqueron.org/virtualization/virtual-machines/1/interfaces/

Ref T1854

Test Plan: Deploy on router-001

Reviewers: dereckson

Maniphest Tasks: T1854

Differential Revision: https://devcentral.nasqueron.org/D3081