Generates the MWC16 NSD and VNFD descriptor packages from source.

To generate the packages type "make". The VNF and NSD packages will be located
build/vnfd_pkgs and build/nsd_pkgs.

To clean, type 'make clean'.

Due to license issues, for the IMS VNFD package, the IMS charm is fetched
extracted from the respective git repository prior to packaging.  Because of
this, internet access is required to reach github.