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/feraligatr.asm

@@ -0,0 +1,10 @@
+; FeraligatrPokedexEntry: ; 0x1cccf9
+	db "BIG JAW@" ; species name
+	dw 707, 1960 ; height, weight
+
+	db   "Although it has a"
+	next "massive body, its"
+	next "powerful hind legs"
+	page "enable it to move"
+	next "quickly, even on"
+	next "the ground.@"