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/power/engines/tesla/energy_ball.dm

@@ -244,7 +244,6 @@
 										/obj/machinery/disposal/deliveryChute,
 										/obj/machinery/camera,
 										/obj/structure/sign,
-										/obj/machinery/gateway,
 										/obj/structure/lattice,
 										/obj/structure/grille,
 										/obj/structure/cable,