Zarr 3 Support #2029
Description
Use zarr 3 for the tile sink.
BLOCKER: Zarr 3 is missing the copy_store function (see zarr-developers/zarr-python#2407). We will either need to move this function into our code or wait for this issue to be resolved.
Workaround: We can get the sqlite functionality through https://github.com/auxym/zarr-sqlite, and that only works on Python >= 3.12 (despite being marked for 3.11). This would need to be added to some of the requirements files for testing. We should probably move some of the tests to output zip instead of sqlite files.
Changes: Zarr 3 has NOT implemented a synchronizer. Instead, we have to explicitly reread group attributes.