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

Move some data into a pokemon/ subdirectory

data/pokemon/dex_entries/drowzee.asm

@@ -0,0 +1,10 @@
+; DrowzeePokedexEntry: ; 0x1b8d0a
+	db "HYPNOSIS@" ; species name
+	dw 303, 710 ; height, weight
+
+	db   "When it twitches"
+	next "its nose, it can"
+	next "tell where someone"
+	page "is sleeping and"
+	next "what that person"
+	next "is dreaming about.@"