Make returning of NICs and VFs of partitions selectable

[andy-maier]

When the zhmc_partition module returns partition properties (i.e. for states stopped|active|fact), it always includes the following artificial properties:

• nics - NICs of the partition
• hbas - HBAs of the partition, for z13
• virtual-functions - VFs of the partition

The inclusion of these artificial properties is currently happening unconditionally. This ticket is to make the inclusion selectable by corresponding expand_... parameters, like they already exist for storage groups and crypto adapters.

A discussion point will be whether the default should be to include them (would be backwards compatible) or not (would be consistent with the other expand_... parameters). I think we should go with backwards compatibility.