feat(schema): Add update_schema action to enable table schema updates

[tomighita]

Which issue does this PR close?

• Closes Add support for adding new fields to an iceberg table #2119.

What changes are included in this PR?

This PR creates an UpdateSchema which implements the TransactionAction allowing users of the crate to add new fields to or delete fields from an iceberg table by updating the table schema. It also checks that the added fields are either optional or have a default value to avoid data corruption downstream.

Are these changes tested?

• Unit tests for UpdateSchema.
• Adds one integration tests which tests that we can add data, update the table and can still read the data, ensuring backwards compatiblity and one integration test for deleting a schema.

[CTTY]

I'm not sure if this is the right direction, exposing add_fields alone in transaction layer seems very limiting. Maybe UpdateSchema can help with your use case?

[tomighita]

Hi @CTTY, this could be an option, indeed. Do you know if this has any chance to be merged? It seems to have no activity for the past 6 months.
I would not mind implementing it myself using the new tx api, just wanted to make sure this would actually get through if it were in a good shape.

[tomighita]

Updated the PR to add an UpdateSchema instead, based on the Java implementation.
Currently, it does not support all actions but we can build on top of this PR to add them as needed.

This also duplicates the work of #1172, but it updates it to match the new Transaction API.

[tomighita]

Also closes #697