Improve handling of underscored property names in input parameters

[andy-maier]

The modules currently require that HMC resource properties are specified with underscores in the property names, where they have hyphens in the HMC WS API book description.

Since all hyphens must be transformed to underscores, the zhmc code could do that automatically, thus accepting both undersorcored names and hyphened names.

This should be done in the following places;

• all modules that get properties as input
• trouble shooting hint in the docs
• maybe: improve the ParameterError message to not just indicate it is not defined in the data model, but to also hint to the case where the data model git additional properties and the zhmc module does not yet support them.