Add `transform_metadata` function to CziReader and AICSImage

[evamaxfield]

Use Case

Please provide a use case to help us understand your request in context
The CZI to OME metadata XSLT project is close to beta testing. Adding a function to the readers (transform_metadata) that transforms their current metadata to OME-4DN would be great to having a unified API for metadata handling.

Solution

Please describe your ideal solution
CziReader.transform_metadata() -> ElementTree
Reader.transform_metadata(): NotImplementedError()
AICSImage.transform_metadata(): self.reader.transform_metadata()

Alternatives

Please describe any alternatives you've considered, even if you've dismissed them

[toloudis]

Alternatives:
get_ome_metadata
get_metadata_as_ome
transform_metadata_to_ome

[evamaxfield]

@MatteBailey this is the goal.

We need to submodule into a new "metadata" module. See also #111

from aicsimageio import AICSImage
from aicsimageio.metadata import transform_czi

# in CziReader
# @property
# def ome_metadata(self) -> OME:
#     return metadata.transform_czi(self.metadata)

img = AICSImage("my-file.czi")
transformed = img.ome_metadata
img.save("converted.ome.tiff", ome=transformed)
# img.save("converted.ome.tiff", transform_metadata=True)