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/dragonite.asm

@@ -0,0 +1,10 @@
+; DragonitePokedexEntry: ; 0x1cc843
+	db "DRAGON@" ; species name
+	dw 703, 4630 ; height, weight
+
+	db   "It is said that"
+	next "somewhere in the"
+	next "ocean lies an"
+	page "island where these"
+	next "gather. Only they"
+	next "live there.@"