VOL-1666: BBSim DHCP Test Case

DHCP IP Addess assignment happens between BBSIM's dhclient, DHCP server
via dhcpl2relay. This is initiated automatically once all ONUs have been
AUTHORIZED.

For the Test Case, we simply verify that all ONUs were assigned an IP
address. We do this using the onos command 'dhcpl2relay-allocations'

A few other minor cleanups were also incorporated
- Dockerfile.onos 1.13.9-rc4 --> 1.13.9
- BBSim hold waits for all ONU's to be AUTHORIZED before proceeding

Change-Id: I863ee241aa904de8267f121fdeb8826298fc1491
diff --git a/tests/atests/common/testCaseUtils.py b/tests/atests/common/testCaseUtils.py
index 9b9b67d..529d540 100755
--- a/tests/atests/common/testCaseUtils.py
+++ b/tests/atests/common/testCaseUtils.py
@@ -172,3 +172,20 @@
 
 def discover_rg_pod_name():
     return extract_pod_name('rg0').strip()
+
+
+def retrieve_authorized_users_device_id_and_port_number(status_line):
+    fields = parse_fields(status_line, ',')
+    deviceField = fields[2].strip()
+    deviceStr, equal, deviceId = deviceField.partition('=')
+    device_Id = deviceId
+    portField = fields[4].strip()
+    portNumStr, equal, portNum = portField.partition('=')
+    portNumber = portNum
+    return device_Id, portNumber
+
+
+def add_subscriber_access(self, device_id, port_number):
+    send_command_to_onos_cli(get_dir(self, 'log'),
+                             'voltha_add_subscriber_access.log', 'volt-add-subscriber-access %s %s'
+                             % (device_id, port_number))