as and SDC user,

i want the pnf to include the softwere version properties.

so that the pnf model can be matched with a pnf avilable and its version

DOD:

1. the PNF will include the softwere_versions propertie.
2. the property will not be mandatory.
3. the property will be a list of strings.
4. the property will be editable using the property assignment string.