[x] Figure out the cause of some append button not appearing
[x] If collection already exists add .001, .002, .003 etc so it can still append
[x] Add the new imported collection into the selected collection
[x] Ensure all categories show up in the UI which have available assets (i can only see about 4)
[x] Add main category folders to directories
[x] Add progress bar to viewport and limit (hidden code) to 6 concurrent downloads. Maybe also put a message "getting download data" before the progress bar starts downloading
[x] Would it be much trouble after appending the object to do Shift+S > Move selection to cursor (so it appends objects where the cursor is)
