implement cactus damage

* Added cactus damage for players and issues the respective death message.

Halts if condition is reached

* style nitpicks

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Co-authored-by: p2r3 <p2r3@p2r3.com>

include/globals.h

@@ -142,6 +142,9 @@
 // every time a block is broken.
 #define ENABLE_PICKUP_ANIMATION
 
+// If defined, players are able to receive damage from nearby cacti.
+#define ENABLE_CACTUS_DAMAGE
+
 // If defined, logs unrecognized packet IDs
 // #define DEV_LOG_UNKNOWN_PACKETS