Add use_emulator setting to better align with object_store crate

[aersam]

Hi there

In many datascience project, fsspec and object_store crate settings are used here and there. I found myself writing a conversion method to convert the settings keys from one to the other and mostly it's pretty easy to do.

• pandas uses fsspec/adlfs
• deltalake uses object_store
• polars uses object_store
• Most python libs use fsspec/adlfs

See https://docs.rs/object_store/latest/object_store/azure/enum.AzureConfigKey.html#variants

Something I miss from adlfs is the use_emulator shortcut for Azure Blob Storage which should result in setting the connection_string to DefaultEndpointsProtocol=http;AccountName=devstoreaccount1;AccountKey=Eby8vdM02xNOcqFlqUwJPLlmEtlCDXJ1OUzFT50uSRZ6IFsuFq2UVErCz4I6tq/K1SZFPTOtr/KBHBeksoGMGw==;BlobEndpoint=http://127.0.0.1:10000/devstoreaccount1;QueueEndpoint=http://127.0.0.1:10001/devstoreaccount1;TableEndpoint=http://127.0.0.1:10002/devstoreaccount1; ( the default connection string of the azure storage emulator)

I think this one should be easy to add and make our lives a little easier :) would also do a PR

[TomAugspurger]

Looks like Azure/azure-sdk-for-python#10040 is a similar issue in the upstream azure.storage.blob library. I think we should follow that.

[aersam]

MSFT does not seem to be willing to implement this, but I still think it would be useful