Process' etc/jvm.config file is now respected by the process launcher

Hi,

Until now `ProcessManagerService` generated empty `etc/jvm.config` file. The file which was also ignored by the process launcher. It was sad, because configuring particular process on the `etc` level might be desired in many situations.

I think that process launcher should respect and read `etc/jvm.config` file, not only the `$FABRIC8_JVM_ARGS` environmental variable (`JVM_ARGS="$FABRIC8_JVM_ARGS"`). I changed the launcher to read `JVM_ARGS` from both `etc/jvm.config` and `$FABRIC8_JVM_ARGS`:

    JVM_ARGS=`cat ${APP_BASE}/etc/jvm.config`"$FABRIC8_JVM_ARGS"

The `etc/jvm.config` can be set from the `process:install-jar` command via `-jvm` (`--jvm-options`) multi-option:

    install-jar -jvm=-XX:+HeapDumpOnOutOfMemoryError -jvm=-server com.groupId my-project 1.0