HPCC-8541 - Add examples illustrating calling Python and Java from ECL

We will want to produce a cleaner / more integrated solution at some point, but
examples of how to call Java ad Python from ECL using embedded C++ may help
as an interim solution.

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
Merge pull request #3829 from richardkchapman/java-python-examples

HPCC-8541 - Add examples illustrating calling Python and Java from ECL

Reviewed-by: Gavin Halliday <ghalliday@hpccsystems.com>