Consider add friendly name() method in Iceberg Table Interface

[jerryshao]

Current Iceberg Table lacks an api to get table name, and relies on toString to get table name, this seems fragile. Also to align with Spark DSv2 Table interface, which requires a name method, so it would be nice to add a name method in Iceberg Table interface.

[aokolnychyi]

I'll submit a PR for this.