[SSSD] Design Document: D-Bus Domains

[Pavel Březina]

https://fedorahosted.org/sssd/wiki/DesignDocs/DBusDomains

Old design: 
https://fedorahosted.org/sssd/wiki/DesignDocs/DBusResponder#Representingdoma...

Hi,
I would like to change D-Bus interface for domains so it takes advantage 
of the new sbus features. It is similar to users and groups. The old 
methods should be deprecated.

It is something we should do to have a consistent interface and we 
should do it rather sooner then later since we don't have many consumers 
at this moment.