Consolidated Metadata Handling

[ilan-gold]

Please describe your wishes and possible alternatives to achieve the desired result.

anndata.io.write_zarr for 0.12 onwards writes consolidated metadata by default. I think this is a good thing for cloud users, but creates consistency issues. Luckily, out write format has the advantage that you need to use our functions specifically to write correctly so we can introcuce a check as in #2015 to handle consolidated metadata.

I am creating this issue to feel out how best to allow users to opt-out of consolidated metadata. The options might be

1. A new argument to write_zarr
2. A setting
3. A clearly stated way of creating a shim class that overrides the property introduced in Allow Stores to opt out of consolidated metadata. zarr-developers/zarr-python#3119 (and then for v2, potentially do nothing thus encouraging people to upgrade).
4. Do nothing (which is similar to option 3) and trust that our handling is good enough