[Service] Added NAT entry into CONTAINER_FEATURE. Fixes #4247. (#4250)

* [Service] Added NAT entry into CONTAINER_FEATURE. Fixes #4247.

Signed-off-by: Andriy Kokhan <akokhan@barefootnetworks.com>

Author: akokhan

files/build_templates/init_cfg.json.j2

@@ -25,7 +25,7 @@
 {% endfor %}
     },
     "CONTAINER_FEATURE": {
-{%- for container in ["bgp", "database", "dhcp_relay", "lldp", "pmon", "radv", "restapi", "sflow",
+{%- for container in ["bgp", "database", "dhcp_relay", "lldp", "nat", "pmon", "radv", "restapi", "sflow",
                       "snmp", "swss", "syncd", "teamd", "telemetry"] %}
         "{{container}}": {
             "auto_restart": "disabled",