Add SchemaUpdate logic to Iceberg-Rust

[Fokko]

The general philosophy of any engine that implements Iceberg-Rust is that they should not care about things like field-IDs. Therefore we try to hide this logic behind APIs. To allow evolution of the schema, we have the UpdateSchema API in Python and the SchemaUpdate (implements UpdateSchema) in Java. It would be good to have this one in Rust as well :)

[vinjai]

Hey @Fokko
I would like to give this a shot

[Fokko]

@vinjai That would be great! Feel free to ping me if you run into anything