Various improvements

* Kotlin upgrade
* Monad usage on APIs
* Idle timeout
* Simulator enhancements

Closes ONAP-390

Change-Id: I3c00fcfe38c722caf661ddaad428cf089eeefcaa
Signed-off-by: Piotr Jaszczyk <piotr.jaszczyk@nokia.com>
Issue-ID: DCAEGEN2-601
43 files changed