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

Move some data into a pokemon/ subdirectory

data/pokemon/dex_entries/phanpy.asm

@@ -0,0 +1,10 @@
+; PhanpyPokedexEntry: ; 0x1d1038
+	db "LONG NOSE@" ; species name
+	dw 108, 740 ; height, weight
+
+	db   "During the desert-"
+	next "ed morning hours,"
+	next "it comes ashore"
+	page "where it deftly"
+	next "uses its trunk to"
+	next "take a shower.@"