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

Move some data into a pokemon/ subdirectory

data/pokemon/dex_entries/electrode.asm

@@ -0,0 +1,10 @@
+; ElectrodePokedexEntry: ; 0x1b8f19
+	db "BALL@" ; species name
+	dw 311, 1470 ; height, weight
+
+	db   "The more energy it"
+	next "charges up, the"
+	next "faster it gets."
+	page "But this also"
+	next "makes it more"
+	next "likely to explode.@"