New starter pathing, beautify Oak's Lab

Please stop asking me about the sprite limit i beg u

Ok so this commit does the following;
- Oak's Lab now uses the Fossil Lab tileset, featuring lots of new contraptions etc to make up for the old removed aides.
- Places the Pikachu and Eevee starters in a new place, which results in a slightly blocky mess, but does the job.
- Fossil Lab tileset graphic has many new things. Lots of bad tiles in the blockset in case we want to use this more.
- Changes the rival's pathing so he, y'know, works on the new map...
- Re-adds the Oak email thing, but I had to do like 4 stupid workarounds because it was broken for unknown reasons. Just made it a generic bg event with no issues.
- Removed the old oak email event; no visible difference.

engine/events/hidden_objects/oaks_lab_email.asm

@@ -1,10 +1,6 @@
-DisplayOakLabEmailText:
-	ld a, [wSpritePlayerStateData1FacingDirection]
-	cp SPRITE_FACING_UP
-	ret nz
-	call EnableAutoTextBoxDrawing
-	tx_pre_jump OakLabEmailText
-
-OakLabEmailText::
-	text_far _OakLabEmailText
-	text_end
+;DisplayOakLabEmailText:
+;	ld a, [wSpritePlayerStateData1FacingDirection]
+;	cp SPRITE_FACING_UP
+;	ret nz
+;	call EnableAutoTextBoxDrawing
+;	tx_pre_jump OakLabEmailText