Add `delete_files`

### Feature Request / Improvement

Hello All,

First of all, apologies as I am not very experienced with PyIceberg.

I currently have a Java application that "manually" updates table metadata and can add new files if they don't exist and replace older files if they already do. This guarantees that, as long as the file names are fixed, I should not have duplicates.

In Java, I use [deleteFile](https://iceberg.apache.org/javadoc/0.13.1/org/apache/iceberg/DeleteFiles.html#deleteFile-java.lang.CharSequence-) and then [addFile](https://iceberg.apache.org/javadoc/0.13.1/org/apache/iceberg/OverwriteFiles.html#addFile-org.apache.iceberg.DataFile-).

In PyIceberg, I can [Add Files](https://py.iceberg.apache.org/api/#add-files), but I don't see options to "Delete Files" or overwrite.

Is `delete_files()` a feature that you could add?

Start with PyIceberg’s existing Add Files API and compare its behavior with the linked Java DeleteFiles and OverwriteFiles APIs. Define the supported delete_files or overwrite semantics and verify that the completed feature lets callers remove or replace existing data files without creating duplicates.

Written by the indexing model from the issue text.