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/cubone.asm

@@ -0,0 +1,10 @@
+; CubonePokedexEntry: ; 0x1b9068
+	db "LONELY@" ; species name
+	dw 104, 140 ; height, weight
+
+	db   "It lost its mother"
+	next "after its birth."
+	next "It wears its"
+	page "mother's skull,"
+	next "never revealing"
+	next "its true face.@"