Construction Truck access for squad leaders only.

Unlock some of the basic building entities from the construction truck. Items like roadblocks, checkpoints, emplacements and fortifications will then be persistent across the map. The idea came from creating our own little side mission. We dressed as civilians, and drove to enemy controlled areas on the map to place radio signal towers, without trying to trigger an enemy response. We then realised it won't let you build the entities with the shovel. Building the towers is now necessary since 1.8 changed the way radio ranges work, so having these at least would be beneficial. I know they can be placed as GM but it feels like cheating 🤣