Add SaveNifti transform to debug transform chain

[Nic-Ma]

Is your feature request related to a problem? Please describe.
Need to add a SaveNifti transform based on the NiftiSaver for debug purpose. May also add SavePNG transform.

[rijobro]

Should it be SaveImage to mirror LoadImage? You could then specify the writer by argument (e.g., Nifti and PNG).

[Nic-Ma]

@rijobro ，

Ideally, it should be SaveImage, I am afraid maybe we can't implement it very well, anyway I can have a try later.
Or do you have interest to implement a SaveImage transform based on our NiftiSaver and PNGSaver?

Thanks.

[rijobro]

Ok, if it's not easy then it's not a high priority. I just thought I would suggest it in case it would save you having to refactor later on.