add control agent configuration

templates/kea-control-agent.conf.j2

+{
+"Control-agent": {
+{%- if network.devices is defined -%}
+{%-   for ifname, ifdata in network.devices.items() if ifdata.services is defined and ("dhcp-ha" in (ifdata.services | default([]))) -%}
+   "http-host": "{{ ifdata.ipv4 | default(ifdata.ipv6 | default('127.0.0.1')) }}",
+   "http-port": {{ kea_control_agent_port }},
+{%-   endfor -%}   
+{%- endif -%}
+   
+
+   "control-sockets": {
+      "dhcp4": {
+        "socket-type": "unix",
+        "socket-name": "/tmp/kea-dhcp4-ctrl.sock"
+      },
+
+      "dhcp6": {
+        "socket-type": "unix",
+        "socket-name": "/tmp/kea-dhcp6-ctrl.sock"
+      }
+    }
+}
+}