Explorer Overhaul and Gateway Retirement (#20855)

* Adds Explorer spawnability, removes Cyberaid gateways

* deletes some REALLY old bloat maps and deletes Gateway.dm

* Fixes runtime, and removes more stuff like gateway config... cause we dont have a gateway anymore

* removes all mention of /obj/machine/gateway

* Goodbye test_tiny and evil_santa 😈

* removed a literal fucking pamphlet

* changes map area name from Gateway to Expedetition

* changes the access from ACCESS_GATEWAY to ACCESS_EXPEDITION

* Revert "Goodbye test_tiny and evil_santa 😈"

This reverts commit eda775ecd5.

* ok deletes evil_santa only

* Fixes a runtime

* Adds new visuals for new area and explorer spawn marker

* Unhides explorers from the pref menu

* adds spawns and fixes the gateways for all maps, adds Expedition room to Cere

* improves and cleans up the expedition room maps, also clothes for Explorers

* GET OUT OF HERE EXAMPLE.

* byebye button

code/modules/arcade/mob_hunt/mob_type_datums.dm

@@ -160,8 +160,7 @@
 						/area/medical/research,
 						/area/crew_quarters/hor,
 						/area/maintenance/asmaint2,
-						/area/teleporter,
-						/area/gateway)
+						/area/teleporter)
 	area_whitelist = list(/area/library,
 						/area/chapel,
 						/area/medical/psych)