Add VNF package sample for practical use cases

There are some samples in current tacker repository, but these represent simple structure and not for users who want to deploy complicated VNF used in commecial environment.
Therefore, it is important to add VNF package sample in order to help them know how to deploy VNF required in commecial use cases.
We intend to add VNF package sample for use cases listed below:
    1) use multiple deployment flavours
    2) deploy VNF connected to external network
    3) deploy VNF as HA cluster
    4) deploy scalable VNF
    5) configure VNF with an ansible memt driver