Removal of zm_lumberyard

[Ion Wonderland.tf]

The map makes it impossible to win as zombies, because the spawn Humans spawn in, is unreachable by the Zombies.

Here's a short demo of the spawn: https://www.mediafire.com/file/0kndz94qjn4rc93/zmlumberyard.dem

I think the map should be removed, because of this.