Incorrect use of 'operation' instead of Resource in the remoting subsystem

Some of the OperationStepHandler impls in the remoting subsystem are reading the data they provide to runtime services from the current operation instead of reading from the current configuration model.

As part of cleaning this up I'll do some conversion of reads of the current address from extracting it from the 'operation' model node to the modern idiom of using OperationContext.getCurrentAddress[Value]().

I'll also convert to AttributeDefinition.resolveModelAttribute in a couple places where not-incorrect but non-standard idioms are used.