Atlas does not support running Solr in standalone(http) mode.
It is especially useful for testing purposes to make setup as simple as possible without Zookeeper. It also enables full integration with JanusGraph as it support both mode of running Solr `cloud` and `http` https://docs.janusgraph.org/index-backend/solr/. Additional benefit is to decouple hbase and solr while running embedded mode so that solr can be run in embbeded mode with external hbase.
- call solr V1 API while creating/updating request handlers in standalone solr
- update atlas start script to enable standalone embedded solr