Improve click detectors

Introduce "gadgets" as a structural function, for items that can be used
when held and when not held. Click detectors are such an item. Make
click detectors correctly attach and use up batteries when used.

src/Dodge/Data/ComposedItem.hs

@@ -14,6 +14,7 @@ import Linear.Quaternion (Quaternion (..))
 
 data ComposeLinkType
     = AmmoInLink Int AmmoType
+    | TriggerLink
     | AmmoModLink
     | AmmoTargetingLink
     | AmmoPayloadLink
@@ -31,6 +32,7 @@ data ItemStructuralFunction
     | GadgetPlatformSF
     | WeaponScopeSF
     | WeaponTargetingSF
+    | TriggerSF
     | AugmentedHUDSF
     | AmmoMagSF AmmoType
     | RemoteScreenSF