feature: Improve file/folder selection UX

[n0samu]

Currently I am using the Buddy API Xtra for file and folder selection dialogs, which displays XP-style dialogs even in Windows 10. Considering the age of Director MX 2004, it doesn't seem like any existing Xtras support the modern Common Item Dialog for file and folder selection. It might be a fun exercise to make my own Xtra for that. 😄

As a shorter-term goal, I should integrate Drop Xtra to allow adding files via drag and drop.