Voltha Alarm Management using OpenNMS and Elasticsearch
- Added necessary configuration to run a self-contained instance of
  OpenNMS
- Elasticsearch/Logstash is responsible for the interception of voltha
  alarms and to forward to OpenNMS

Amendment:
- Cleaned up untouched opennms config files
- Added Dockerfile and scripts to override the default entrypoint script

Change-Id: Id611a330f7274d016281e734ade79d22bfc0356b
diff --git a/compose/opennms/env/opennms.env b/compose/opennms/env/opennms.env
new file mode 100644
index 0000000..66d6fa8
--- /dev/null
+++ b/compose/opennms/env/opennms.env
@@ -0,0 +1,8 @@
+# Environment variables for OpenNMS database connection
+OPENNMS_DBNAME=opennms
+OPENNMS_DBUSER=opennms
+OPENNMS_DBPASS=opennms
+OPENNMS_HOME=/opt/opennms
+OPENNMS_DB_CONFIG=/opt/opennms/etc/opennms-datasources.xml
+opennms.rtc.event.proxy.host=0.0.0.0
+