Move palisades from other/ to structures/
Following D1881 which introduced a common parent, palisade templates can be moved:
- other/palisades_rocks_* to structures/palisades_*
- other/palisades_*_spike* to structures/palisades_spike*
Map scripts were updated accordingly.
Patch By: Nescio
Reviewed By: wraitii
Refs #4770
Differential Revision: https://code.wildfiregames.com/D2234