demo: add inventory

demo/inventory/1-cesnet.yaml

+---
+fip:
+  hosts:
+    147.251.124.120:
+
+master:
+  hosts:
+    2001:718:801:432:f816:3eff:fe39:d427:
+      # must be IPv4 address or hostname
+      kube_server: 192.168.0.253
+
+ingress:
+  hosts:
+    2001:718:801:432:f816:3eff:fed7:af8a:
+
+nfs:
+  hosts:
+    2001:718:801:432:f816:3eff:fede:8e76:
+
+worker:
+  hosts:
+    2001:718:801:432:f816:3eff:fe86:e0e5:
+    2001:718:801:432:f816:3eff:fe1a:4c1f:
+
+# using public IP of kube_server for ansible delegate_to
+kube_server:
+  hosts:
+    192.168.0.253:
+      ansible_host: 2001:718:801:432:f816:3eff:fe39:d427