[Process manager] Folks can now easily enable JVM debug on managed process.

Hi,

Yet another pull request from "making Fabric8 a devops heaven" series. If something goes wrong with the managed process and folks need to debug it with IDE, all we need to do is to set FABRIC8_JVM_DEBUG environmental variable to TRUE:

     FABRIC8_JVM_DEBUG=TRUE bin/launcher start

And connect to the managed process using JDWP on port 5005 (default IntelliJ's port for debugger).

We could add some options to customize `port` and `suspend` parts of the JDWP agent in the future, but default `-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=5005` should be sufficient for the majority of the cases for a while.

Cheers.