Migration to new event defination for OpenONU adapter

     This commit is for the migation of alarms and kpi fw in
     pyvoltha to the new event fw and has the following changes:

     1. Alarms definations are changed to events and modified accordingly
        to incorporate the changes in event proto message

     2. Kpis module is also moved under the events fw

Change-Id: Icfbb28e364b662ea8483b7472fe21ddf4551372e
diff --git a/pyvoltha/adapters/extensions/events/device_events/heartbeat_events.py b/pyvoltha/adapters/extensions/events/device_events/heartbeat_events.py
new file mode 100644
index 0000000..39386f2
--- /dev/null
+++ b/pyvoltha/adapters/extensions/events/device_events/heartbeat_events.py
@@ -0,0 +1,27 @@
+# Copyright 2017-present Adtran, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+from voltha_protos.events_pb2 import EventCategory, EventSubCategory
+from adapter_events import DeviceEventBase
+
+
+class HeartbeatEvent(DeviceEventBase):
+    def __init__(self, event_mgr, raised_ts, object_type='olt', heartbeat_misses=0):
+        super(HeartbeatEvent, self).__init__(event_mgr, raised_ts, object_type,
+                                             event='Heartbeat',
+                                             category=EventCategory.EQUIPMENT,
+                                             sub_category=ventSubCategory.PON)
+        self._misses = heartbeat_misses
+
+    def get_context_data(self):
+        return {'heartbeats-missed': self._misses}