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

Move some data into a pokemon/ subdirectory

data/pokemon/dex_entries/wobbuffet.asm

@@ -0,0 +1,10 @@
+; WobbuffetPokedexEntry: ; 0x1d03dd
+	db "PATIENT@" ; species name
+	dw 403, 630 ; height, weight
+
+	db   "In order to con-"
+	next "ceal its black"
+	next "tail, it lives in"
+	page "a dark cave and"
+	next "only moves about"
+	next "at night.@"