Consider adding folder in the root of product download archives

At !73 (comment 10795), @ahofkamp noted:

Unpacking the archive will splash its contents all over the place, since the archive doesn't start with a directory prefix [...]

and

In case the 'splash' is not clear, this is what I got after unpacking:

$ ls -F
artifacts.xml  bin/  configuration/  eclipse*  eclipse.ini  features/  license.html  p2/  plugins/  readme/

(the trailing / are from the -F option)

Now if you didn't unpack in a fresh empty directory, but in your average Downloads destination directory with a few hundred files and directories, the user will never find the unpacked files again. So please archive a eclipse-escet-incubation-ide-0.2.0.20210517-171328-linux.gtk.x86_64 directory rather than *.