Rename all files in data/pokedex/entries/

Some people suggested this would be a good idea, and make management of
the files easier. I'm inclined to agree.

data/pokedex/entries/voltorb.asm

@@ -0,0 +1,10 @@
+; VoltorbPokedexEntry: ; 0x1b8eb0
+	db "BALL@" ; species name
+	dw 108, 230 ; height, weight
+
+	db   "During the study"
+	next "of this #MON,"
+	next "it was discovered"
+	page "that its compo-"
+	next "nents are not"
+	next "found in nature.@"