Consistent ordering of domain and non-domain arguments for standard operators

Currently, the order in which arguments shall be provided differs between operators, e.g. ift.from_global_data and ift.full both take the domain as first argument, while ift.ScalingOperator requires the factor with which to scale a field as first argument and the domain as second. Moving to NIFTY6 might be the perfect opportunity to fix this either by consistently requiring the domain to be e.g. the first argument or by making the ift.ScalingOperator more flexible by swapping arguments in a suitable manner during initialization.