Add files command to list the current snapshot files.

[subkanthi]

./pyiceberg files test.ll2
Snapshots: test.ll2
└── Snapshot 4169635612430693116, schema 0: s3://bucket1/test/ll2/metadata/snap-4169635612430693116-0-b4b4fa9a-4d7a-4be4-9baa-87ab86d3e91d.avro
    └── Manifest: s3://bucket1/test/ll2/metadata/b4b4fa9a-4d7a-4be4-9baa-87ab86d3e91d-m0.avro
        └── Datafile: /Users/kanthi/Downloads/updated_file.parquet

The describe command also lists this info except the datafile, this is very handy to idenify the current datafile/snapshot/manifest referred by tables.