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/caterpie.asm

@@ -0,0 +1,10 @@
+; CaterpiePokedexEntry: ; 0x181a60
+	db "WORM@" ; species name
+	dw 100, 60 ; height, weight
+
+	db   "It crawls into"
+	next "foliage where it"
+	next "camouflages itself"
+	page "among leaves that"
+	next "are the same color"
+	next "as its body.@"