Add physical network doc again

This was deleted by mistake

source/physical_network.rst

@@ -0,0 +1,19 @@
+.. include:: vars.rst
+
+================
+Physical network
+================
+
+.. ifconfig:: deployment['kayobe_manages_physical_network']
+
+   The |project_name| deployment uses Kayobe to manage the physical network.
+
+   .. ifconfig:: deployment['physical_network_evpn']
+
+      .. include:: include/evpn_fabric_overview.rst
+
+      .. include:: include/evpn_fabric_details.rst
+
+.. ifconfig:: not deployment['kayobe_manages_physical_network']
+
+   The |project_name| deployment does not use Kayobe to manage the physical network.