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

Move some data into a pokemon/ subdirectory

data/pokemon/dex_entries/lickitung.asm

@@ -0,0 +1,10 @@
+; LickitungPokedexEntry: ; 0x1b9210
+	db "LICKING@" ; species name
+	dw 311, 1440 ; height, weight
+
+	db   "It has a tongue"
+	next "that is over 6'6''"
+	next "long. It uses this"
+	page "long tongue to"
+	next "lick its body"
+	next "clean.@"