Better ways for storing notion_urls

[lolipopshock]

The current way of saving notion_urls in notion_df is not perfect:

df.notion_urls = pd.Series([ele["url"] for ele in database_query_results])
df.notion_ids = pd.Series([ele["id"] for ele in database_query_results])

For example, after running df.copy(), this value would disappear. Try to figure out a better way to do so.