Move away UnrealEngine/UnrealEngineLauncher from $HOME/Documents to $HOME/Library/Preferences

I understand that Unreal Editor creates $HOME/Documents/Unreal Projects folder containing created projects, but it does also create two additional folders UnrealEngine/UnrealEngineLauncher which are internal app preference files, which shall go into $HOME/Library/Preferences instead, since they don’t belong to user space:

You’re right, Documents is not a good place for these files. We did change that recently, so that we store files in $HOME/Library/Application Support/Epic instead of $HOME/Documents, but it was to late for this change to make it to the version we released. It will be fixed in 4.1 build.