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/jolteon.asm

@@ -0,0 +1,10 @@
+; JolteonPokedexEntry: ; 0x1cc28b
+	db "LIGHTNING@" ; species name
+	dw 207, 540 ; height, weight
+
+	db   "The negatively"
+	next "charged ions"
+	next "generated in its"
+	page "fur create a"
+	next "constant sparking"
+	next "noise.@"