fix(objects): split Vlan SVIs and IPs for load ordering — refs #52

InfraInterfaceVlan references InfraVLAN objects (06-vlans-vxlan.yml),
so Vlan SVIs must load after VLANs. Similarly, Vlan IP addresses
reference Vlan SVIs.

Changes:
- Extract InfraInterfaceVlan from 04 into 07-interface-vlans.yml
- Extract Vlan SVI IPs from 05 into 08-ipam-vlans.yml
- Rename 07-bgp→09, 08-vrfs→10, 09-mlag→11
- Update .infrahub.yml with new 11-file load order

Load order: foundation → fabric → devices → interfaces (Lo/Lag/Eth)
→ ipam (Lo/Eth) → vlans-vxlan → interface-vlans → ipam-vlans
→ bgp → vrfs → mlag

.infrahub.yml

@@ -10,6 +10,8 @@ objects:
   - objects/04-interfaces.yml
   - objects/05-ipam.yml
   - objects/06-vlans-vxlan.yml
-  - objects/07-bgp.yml
-  - objects/08-vrfs.yml
-  - objects/09-mlag.yml
+  - objects/07-interface-vlans.yml
+  - objects/08-ipam-vlans.yml
+  - objects/09-bgp.yml
+  - objects/10-vrfs.yml
+  - objects/11-mlag.yml