As that environment variable can contain elasticsearch specific configuration
like the path to a configuration, it makes sense to support in both
elasticsearch commands.
Closes#8288
When launching multiple nodes in MS Windows env, batch command window does not come by default with any title.
This patch add `Elasticsearch VERSION` as a title, where VERSION is the current elasticsearch version.
Same for `plugin.bat` and `service.bat`.
Closes#6336Closes#6752