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

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.

Start by reviewing the linked spatialdata-io issue and pull request, then inspect the existing python -m spatialdata_io convert entry point shown in the examples. Clarify the final command syntax and scope for writing, concatenating, removing, and renaming SpatialData elements. Done means the agreed modular operations work from the CLI without Python code.