Refactor of pnf-simulator to nf-simulator and AVCN-manger open sourcing

Refactor of pnf-simulator to nf-simulator and AVCN-manger open sourcing

After agreement with Morgan we decided to:
- refactor pnf-simulator,
- rename it (old repo will be terminated after changes) to
nf-simulator,
- divide into subcomponents
- open source AVCN part responsible for reporting any configuration change
happening due to multiple reasons via netconf in symulator to
the network management system, using ONAP  VES CM change events

Issue-ID: INT-1869
Signed-off-by: Krzysztof Kuzmicki <krzysztof.kuzmicki@nokia.com>
Change-Id: I8d54564da1aa0004632dacc16a906e730eed8f16