Move other/wallset_palisade to structures/wallset_palisade, refs #4770, D1002, D1798.
Differential Revision: https://code.wildfiregames.com/D1881
Patch By: Nescio
While at it, fix ESLint overshadowing warning in survival triggers from rP18209, unnoticed in rP18430 and rP19359 but noticed by Jenkins.