cant remote debug with Java9 +

[TemaniH]

Can't remote debug when working with Java 9+.

play1/framework/pym/play/application.py

Line 308 in e7b25e0

java_args.append('-Xrunjdwp:transport=dt_socket,address=%s,server=y,suspend=n' % self.jpda_port)

address arg has no ip address/hostname.

suggested solutions:

• expose new jdpa_host config param and if set use new syntax.
• resolve what java version is running and set accordingly.
• combine the 2 options and allow jdpa_host config param to have default value.

referencies:

• https://www.oracle.com/technetwork/java/javase/9-notes-3745703.html#JDK-8041435
• https://dev-aux.com/java/java-local-and-remote-jvm-debugging-jdk-8-and-later

[holajsh]

As this is very annoying problem when running Play app in a Docker container I have done a PR for this.