Update a TableSchema from a Schema

[Fokko]

To make things easier for query engines to evolve schemas into a target schema, it would be great to add UnionByName to Iceberg-Rust as well. The UnionByName visitor (python, java) to make extending of the schema easy. For example, see the Python docs on Union by Name.

For example, if you have a CDC application, and you see a new schema, you can just pass it into this method to update the table. It will traverse the schema and compare it based on the names.

Depends on #697

[Lordworms]

I would like to do this one.