Split items/ and trainers/ into their data/ and engine/ components

Move some data into a pokemon/ subdirectory

data/pokemon/dex_entries/girafarig.asm

@@ -0,0 +1,10 @@
+; GirafarigPokedexEntry: ; 0x1d0446
+	db "LONG NECK@" ; species name
+	dw 411, 910 ; height, weight
+
+	db   "When it is in"
+	next "danger, its tail"
+	next "uses some sort of"
+	page "mysterious powers"
+	next "to drive away the"
+	next "enemy.@"