removed JAVA_HOME env variable from supervisor configuration

* not needed and is causing some problems since we switched from
  the eclipse-temurin to the ubuntu base image.

see #489

src/scripts/jsonrpc2-helper.go

@@ -12,7 +12,6 @@ import (
 
 const supervisorctlConfigTemplate = `
 [program:%s]
-environment=JAVA_HOME=/opt/java/openjdk
 process_name=%s
 command=bash -c "nc -l -p %d <%s | signal-cli --output=json --config %s jsonRpc >%s"
 autostart=true