HPCC-9946 Add support for JVM settings in environment.conf

Set using jvmoptions=XXX in environment.conf. Use ENVSEPCHAR to separate

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
Merge pull request #4837 from richardkchapman/jvm-settings

HPCC-9946 Add support for JVM settings in environment.conf

Reviewed-by: Gavin Halliday <ghalliday@hpccsystems.com>