Default shortcut for opening Appfinder

Currently the default shortcut for opening the Appfinder in uncollapsed mode is Alt+F3, which is not very convenient or intuitive.

It would be nice to have Alt+Space as the default shortcut, similar to the shortcut for opening KRunner in KDE.

It would run "xfce4-appfinder" without the "--collapsed" flag.

Some people might be used to Alt+F3, so it would be better to keep both shortcuts at the same time.

This would solve a 13 year old problem (#1 (closed)), where many users who comment on this issue want to open the Whisker Menu with the Super key, as they would have a different but easy and similar way to type and open a program without using the mouse.