Optional fsspec filesystems

[legout]

Description

Make Python filesystem spec (fsspec) optional available in delta-rs.

Use Case

One could easily cache metadata files/delta log using fsspecs SimpleCacheFileSystem with s3fs, gcsfs or adlfs. This might improve read performance.

[ion-elgreco]

We won't support fsspec filesystems since we use object store. You can create a custom object store which does caching and make a PR to add this store that can be enabled with a storage option