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/postgres.env b/compose/opennms/env/postgres.env
new file mode 100644
index 0000000..8f95df4
--- /dev/null
+++ b/compose/opennms/env/postgres.env
@@ -0,0 +1,5 @@
+# Environment variables for generic PostgreSQL server
+POSTGRES_HOST=database
+POSTGRES_PORT=5432
+POSTGRES_USER=postgres
+POSTGRES_PASSWORD=postgres