is a Magician essentially the same as MultiZarrToZarr ?

As pointed out by @martindurant at [this comment](https://github.com/fsspec/kerchunk/issues/127#issuecomment-1131913031), (some of) the functionality of the Magician workflow might be possible to implement using [`MultiZarrToZarr`](https://fsspec.github.io/kerchunk/reference.html#kerchunk.combine.MultiZarrToZarr).

We might want to investigate this and try to simplify code if possible.