VMFest should not enforce Pallet requirements in setup-model

[tbatchelli]

Adding support for Vagrant Boxes in VMFest also added the requirement that certain Pallet metadata fields be passed when calling setup-model. see https://github.com/tbatchelli/vmfest/commit/29d4256ed0f125e9b318f6ea7cdda04c436ff15c .

There are use cases other than Pallet-vmfest that need to be honoured.

VMFest should not impose such requirements, and pallet-vmfest should be checking for those fields instead.