Gym Leader Rematches!

This commit adds a large fundamental change to KEP, that being Gym Rematches.

This is achieved alongside a rework to the script that makes those post-game-gating NPCs shift around. If you add a new one, just add its constant to the lists you'll see in the Hall of Fame script.

It also fixes a few bugs:
- Fixed a bug where Cinnabar Gym loaded a fleet of Blaines. This occurred due to the way he is coded at base, and a misunderstanding I had when implementing his scaling. This is now fixed by standardising his gym script instead, while letting the gym trainers still use the old one.
- Fixed a bug where the Up-Grade NPC would not appear after beating Silph Co. 11F. However, Giovanni currently seems to have trouble with his text. This floor needs some re-coding anyway, given we need to add Jessie and James to it.

And some misc. changes:
- Changed the first Moon Stone in Mt. Moon to a Poison Stone for the Nidoking speedrunners
- Debug Mode now has a line of code to set up the post-game easily
- Changed Surge's initial battle text to Yellow's
- Added Sabrina's more accurate LGPE initial battle text, referring to the spoon she bent by accident

engine/debug/debug_party.asm

@@ -56,6 +56,9 @@ IF DEF(_DEBUG)
 	ld a, MEOWTH
 	ld [wBeautyChoice], a
 	
+	; Test Post-Game Functionality.
+	SetEvent EVENT_POST_GAME_ATTAINED
+	
 	; Get all badges except Earth Badge.
 	ld a, ~(1 << BIT_EARTHBADGE)
 	ld [wObtainedBadges], a
@@ -180,6 +183,7 @@ DebugItemsList:
 	db FULL_RESTORE, 99
 	db MAX_REPEL, 99
 	db RARE_CANDY, 99
+	db ESCAPE_ROPE, 99
 	db POKE_BALL, 99 ; test ball miss text with this
 	db SECRET_KEY, 1
 	db CARD_KEY, 1