Extend topology with Core, Campus fabric and DC Border Leafs

Add node declarations and links for:
- DC Border Leaf MLAG pair (border-leaf-dc1/2)
- Core routers (core1, core2) interconnected via eth5
- Campus spines, leafs, border leafs, access switches and two hosts
- DC spine eth9/eth10 uplinks toward DC Border Leafs (underlay + EVPN)

configs/spine1.cfg

@@ -81,6 +81,19 @@ interface Ethernet8
    ip address 10.0.1.14/31
    mtu 9214
 !
+! Underlay P2P interfaces to DC Border Leafs
+interface Ethernet9
+   description border-leaf-dc1
+   no switchport
+   ip address 10.0.1.16/31
+   mtu 9214
+!
+interface Ethernet10
+   description border-leaf-dc2
+   no switchport
+   ip address 10.0.1.18/31
+   mtu 9214
+!
 ! BGP Configuration
 router bgp 65000
    router-id 10.0.250.1
@@ -98,6 +111,8 @@ router bgp 65000
    neighbor 10.0.1.11 remote-as 65003
    neighbor 10.0.1.13 remote-as 65004
    neighbor 10.0.1.15 remote-as 65004
+   neighbor 10.0.1.17 remote-as 65005
+   neighbor 10.0.1.19 remote-as 65005
    !
    ! EVPN peer-group configuration
    neighbor evpn peer group
@@ -125,6 +140,12 @@ router bgp 65000
    neighbor 10.0.250.18 peer group evpn
    neighbor 10.0.250.18 remote-as 65004
    !
+   ! EVPN neighbors (to DC border-leaf loopbacks)
+   neighbor 10.0.250.21 peer group evpn
+   neighbor 10.0.250.21 remote-as 65005
+   neighbor 10.0.250.22 peer group evpn
+   neighbor 10.0.250.22 remote-as 65005
+   !
    ! IPv4 address family
    address-family ipv4
       neighbor 10.0.1.1 activate
@@ -135,6 +156,8 @@ router bgp 65000
       neighbor 10.0.1.11 activate
       neighbor 10.0.1.13 activate
       neighbor 10.0.1.15 activate
+      neighbor 10.0.1.17 activate
+      neighbor 10.0.1.19 activate
       network 10.0.250.1/32
    !
    ! EVPN address family