QubesOS/qubes-issues#853
It doesn't make sense to send mgmt call to _named_ VM just to ask for its name. Use value that QubesVM object already have. This also means we can safely access vm.name, no need to touch any private attribute. QubesOS/qubes-issues#853
Don't shadow builtin 'property' type. We don't need to kee compatibility with actual core3 implementation yet, so don't make the same mistake twice.
First minimal version, with just listing VMs and handling properties. QubesOS/qubes-issues#853
