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/meowth.asm

@@ -0,0 +1,10 @@
+; MeowthPokedexEntry: ; 0x182c08
+	db "SCRATCHCAT@" ; species name
+	dw 104, 90 ; height, weight
+
+	db   "It loves things"
+	next "that sparkle. When"
+	next "it sees a shiny"
+	page "object, the gold"
+	next "coin on its head"
+	next "shines too.@"