Report Capable interfaces - refactor as decorator

[oesteban]

I think they would be useful to quickly create new interfaces with ability to write visual reports.

Something like:

@report(
    kind='registration',
    fixed='inputs.fixed_image',
    moving='outputs.warped_image',
    labels={'fixed': 'MNI152NlinAsym2009c', 'moving': 'sub-11101'},
)
class ANTSRPT(nipype.interfaces.ants.Registration):
    pass

There would be two kinds (in principle): registration and segmentation. The registration one flickers between moving and fixed.

WDYT (provided we give this very low priority)?