Add Salt configuration for FRRouting OSPF on routers.
The IntraNought network will be shared to Windriver and Ysul.
Two GRE tunnels (gre1 and gre2) are established over this network to provide direct point-to-point links between each router and Windriver and Ysul.
OSPF is configured on gre1, gre2, and vmx0. However, OSPF neighbor relationships and route exchange take place only on gre1 and gre2, as these interfaces are explicitly set as non-passive using no ip ospf passive. The vmx0 interface remains passive.
Each router has a unique OSPF router-id (RID) to ensure correct neighbor
relationships. RID are not real IP addresses, but arbitrary 32 bits values.
The OSPF cost for interface gre1 is left to its default (10) value for now and will be adjusted
later depending on which router is active.
Ref T2303