Added Airdrop Despawn Time Seconds config option to specify how long an airdrop remains before despawning. To disable despawning, set this value to 0 or any negative number.
Added DropAirdropExactlyAtSupplySignalPosition config option to control whether the airdrop is dropped exactly at the supply signal's position or at a random position around the supply signal.
Added SupplySignalSmokeDurationSeconds config option to customize the duration of the supply signal smoke.
Introduced OnSupplySignalExplode hook which is called when a supply signal is about to explode.
