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/drowzee.asm

@@ -0,0 +1,10 @@
+; DrowzeePokedexEntry: ; 0x1b8d0a
+	db "HYPNOSIS@" ; species name
+	dw 303, 710 ; height, weight
+
+	db   "When it twitches"
+	next "its nose, it can"
+	next "tell where someone"
+	page "is sleeping and"
+	next "what that person"
+	next "is dreaming about.@"