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

Move some data into a pokemon/ subdirectory

data/pokemon/dex_entries/chinchou.asm

@@ -0,0 +1,10 @@
+; ChinchouPokedexEntry: ; 0x1cd165
+	db "ANGLER@" ; species name
+	dw 108, 260 ; height, weight
+
+	db   "Its antennae, whi-"
+	next "ch evolved from a"
+	next "fin, have both po-"
+	page "sitive and neg-"
+	next "ative charges flo-"
+	next "wing through them.@"