CLI for modular creation/edit/concatenation of `SpatialData` objects

[LucaMarconato]

Related to https://github.com/scverse/spatialdata-io/issues/231 and https://github.com/scverse/spatialdata-io/pull/72.

We could enable a way to merge/edit spatialdata stored objects in a modular way without having to use Python code.

a possible example

The first part here assumes the two issues linked above are solved (note, this is a draft syntax, the final one may be different)

python -m spatialdata_io convert xenium path/to/raw/data path/to/output/zarr/store
python -m spatialdata_io convert tiff path/to/tiff/file path/to/output/zarr/store2 --name "my_image"

New proposed CLI (this is one of possible design to discuss):

python -m spatialdata write_element --from path/to/output/zarr/store2/images/my_image --to path/to/output/zarr/store

Equivalent syntax for concatenating SpatialData objects and for removing/renaming elements from an object.