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?

從 PyIceberg 現有的 Add Files API 開始，並將其行為與連結的 Java DeleteFiles 和 OverwriteFiles API 進行比較。定義支援的 delete_files 或 overwrite 語意，並驗證已完成的功能能讓呼叫端移除或取代現有資料檔案，而不會建立重複項目。

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