Support advanced NVP IPsec VPN Service

The patch adds NVP advanced IPsec VPN Service support for NVP with VCNS:
    * NVP IPsec VPN is an  advanced Service depending on NVP
      advanced service router
    * NVP IPsec VPN Service will finally call VCNS IPsec VPN bulk
      reconfiguration to map to VPN DB logic

Implements: blueprint nvp-vpnaas-plugin
Change-Id: Ic8a96f5defc2b868c6f18fb4966b04079d3c781a
Merge "Support advanced NVP IPsec VPN Service"