Configure memory usage

I saw a pull-request opened a while back that introduced the possibility of analyzing bigger than memory datasets by saving some of the state on disk, I was wondering if there is a way for the user to configure the maximum amount of memory the process can use?

Like `duckdb` has `"SET max_memory='1GB';"`

先找出先前為大於記憶體的資料集新增磁碟後端狀態的 pull request，接著追蹤使用者如何在 Python bindings 中設定執行設定。定義使用者可設定的記憶體限制應如何運作，包括它與磁碟後端處理的互動，並加入 coverage 以顯示已設定的限制確實受到遵守。

由索引模型根據 Issue 內容生成。