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/girafarig.asm

@@ -0,0 +1,10 @@
+; GirafarigPokedexEntry: ; 0x1d0446
+	db "LONG NECK@" ; species name
+	dw 411, 910 ; height, weight
+
+	db   "When it is in"
+	next "danger, its tail"
+	next "uses some sort of"
+	page "mysterious powers"
+	next "to drive away the"
+	next "enemy.@"