[Gameplay A24] - Allow building palisades in neutral territory.

This is a rather controversial change, so if it feels compleatly off, we should revert.
The game is Alpha, so try anyways.

Patch by: @Nescio
Differential revision: D2507
Accepted by: @borg-, @Lionkanzen,
In favour: @borg-, @Lionkanzen, @wraitii
Reservations: @elexis, @Feldfeld, @badosu
Reservations against former patch: @chrstgtr, @PhyZic, @Stan, @ValihrAnt