Add Campus EVPN-VXLAN fabric configs and host interfaces

- campus-spine1/2 (AS 66000): eBGP underlay + EVPN RR toward leafs
  and border leafs, addressing plan 10.1.x.x.
- campus-leaf1/2 (VTEP1, AS 66001, VTEP 10.1.255.11): VLAN 50
  (stretched L2 VXLAN, VNI 110050) and VLAN 60 (VRF gold anycast
  10.60.60.1, L3 VNI 100001).
- campus-leaf3/4 (VTEP2, AS 66002, VTEP 10.1.255.12): VLAN 50 and
  VLAN 70 (VRF gold anycast 10.60.70.1).
- border-leaf-campus1/2 (AS 66005, VTEP 10.1.255.21): MLAG pair,
  OSPF + eBGP to cores, VRF gold stitched via vxlan vrf gold
  vni 100001 with RT 1:100001.
- campus-access1/2: L2-only uplinks to campus leaf MLAG pairs,
  trunks VLAN 50+60 / 50+70.
- campus-host1/2 interface files: bond0 + VLAN sub-interfaces for
  the stretched L2 VLAN 50 and the VRF gold subnets.

configs/campus-access1.cfg

@@ -0,0 +1,68 @@
+! Campus-Access1 Configuration
+! L2-only access switch for Campus VTEP1 (campus-leaf1/leaf2)
+!
+hostname campus-access1
+!
+! LLDP Management0
+lldp management-address Management0
+!
+! enable gNMI API
+management api gnmi
+   transport grpc default
+   provider eos-native
+!
+! admin/admin for ssh access
+username admin privilege 15 role network-admin secret sha512 $6$xQktFrbdeqEhVzLM$.1wOJB25nw2fqYaSXDu6y4mo6AP9hngMCFe2vGDl84hWoz00Q.4unoEBqspNI0HEoRz.OZhdBHqQv12KABf0B0
+!
+! VLANs
+vlan 50
+   name test-l2-vxlan-campus
+!
+vlan 60
+   name vrf-gold-campus-subnet1
+!
+! Management interface
+interface Management0
+   ip address 172.16.0.61/24
+!
+! Spanning-tree
+spanning-tree mode mstp
+spanning-tree edge-port bpduguard default
+!
+! Uplink to campus leaf MLAG pair (Port-Channel 10)
+interface Ethernet1
+   description campus-leaf1-uplink
+   channel-group 10 mode active
+!
+interface Ethernet2
+   description campus-leaf2-uplink
+   channel-group 10 mode active
+!
+interface Port-Channel10
+   description uplink-to-campus-leaf-mlag
+   switchport mode trunk
+   switchport trunk allowed vlan 50,60
+   no shutdown
+!
+! Host-facing downlink (Port-Channel 1)
+interface Ethernet3
+   description campus-host1
+   channel-group 1 mode active
+!
+interface Ethernet4
+   description campus-host1
+   channel-group 1 mode active
+!
+interface Port-Channel1
+   description campus-host1
+   switchport mode trunk
+   switchport trunk allowed vlan 50,60
+   port-channel lacp fallback timeout 5
+   port-channel lacp fallback individual
+   spanning-tree portfast
+   no shutdown
+!
+! Default route for management
+ip route 0.0.0.0/0 172.16.0.254
+!
+end