Global option --realm missing

[gpaterno]

The global option --realm missing from python securepass-tools porting
This set the REALM post variable in case the keys are capable of performing multi-realm operations.

[alessio]

The option --realm wasn't handled in the application's global configuration scope, instead it was implemented by all those single sp-* tools that supported REALM overriding.

[alessio]

Should we plan work on this? We're quite happy about the current options handling mechanism, we'll review this after the first release will be out.