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

Move some data into a pokemon/ subdirectory

data/pokemon/dex_entries/machoke.asm

@@ -0,0 +1,10 @@
+; MachokePokedexEntry: ; 0x1b80cb
+	db "SUPERPOWER@" ; species name
+	dw 411, 1550 ; height, weight
+
+	db   "This tough #MON"
+	next "always stays in"
+	next "the zone. Its"
+	page "muscles become"
+	next "thicker after"
+	next "every battle.@"