Flag to get return properties with underscores

[andy-maier]

We are trying to make life easier for Ansible users in the input parameters because they all have underscores instead of hyphens: With underscores, something like vars.boot_ftp_username is possible, while with hyphens it would have been vars['boot-ftp-username'].

On the return properties, many older modules are not translating the names of properties received from the HMC from hyphens to underscores. We have started doing that in some of the newer modules, but we need to keep older modules compatible.

This ticket is to add an optional input parameter return_underscores to the older modules that causes the names of properties in the module return value to be translated from hyphens to underscores.