Add volume to Docker Compose elasticsearch-opendrr service

[anthonyfok]

Thank you Arash, Drew and Joost for help clearing my confusion regarding my newbie question about Elasticsearch data storage, as well as difference between Docker stop and down, at the Cloud Tech meeting earlier today. You have given me the confidence to pursue this further.

After some local exploration with docker exec -it opendrr-api_elasticsearch-opendrr_1 /bin/bash, and a Google search on "Docker Elasticsearch volume", it turns out that the docs suggest setting /usr/share/elasticsearch/data as Docker named volumes, see

• Install Elasticsearch with Docker | Elasticsearch Guide [7.13] | Elastic
• Running the Elastic Stack on Docker | Getting Started [7.13] | Elastic

Worth looking into, and see if there are other parameters that we are interested in adding.