Fixed the Ballista, it should no longer crash the serverserver

Fixed the inital cost to no longer be free,
Also edited the building recipe

quick hotfix

updated to be compatible with newest update

updated the hitbox so repairing should be easier, also possibly fixed the icons showing up incorrectly

Made the gun uncollidable with other walkers due to unintended shoving powers

Fixed upgrades to be able to be made with dinghy blueprints

disabled ballista HP so it can no longer be destroyed

fixed wrong icon showing up in the building menu