Draft: fuse: Add a FUSE based virtual FS for drag-to-extract

Previously we use some X11 API to get the drop target path and extract files there, but now with GTK4's new DnD API, we cannot get the drop target path and must prepare source before drop, but extracting is an async operation so it's hard to do this.

This commit adds a FUSE based virtual file system, when dragging a file we provide the path on the virtual FS, then do extracting when virtual FS gets reading requests.

Fixes #4.