fix(objects): wrap all relation references as HFID lists — refs #52

All relation values now use the HFID list-of-strings format required
by infrahubctl:
- Cardinality one: device: ["spine1"], platform: ["arista_eos"]
- Cardinality many: devices: - ["leaf1"], networks: - ["10.0.250.1/32"]
- Composite HFIDs unchanged: peer_group: ["10.0.250.1", "evpn"]

Files modified: 02-fabric, 03-devices, 04-interfaces, 06-vlans-vxlan,
07-bgp, 08-vrfs, 09-mlag (05-ipam already correct).

objects/02-fabric.yml

@@ -10,6 +10,6 @@ spec:
       underlay_protocol: ebgp
       overlay_protocol: evpn
       anycast_gateway_mac: "c001.cafe.babe"
-      spine_asn: "65000"
+      spine_asn: ["65000"]
       sites:
-        - dc1
+        - ["dc1"]