Add arrivals (#14755)

* Arrivals

* More arrivals and shitty uhh preload

* cvar

* a

* clockin + maps

* shitter prevention

* Placement

* a

* cvar for tests and dev

* weh

Content.Server/Shuttles/Components/ClockedInComponent.cs

@@ -0,0 +1,11 @@
+namespace Content.Server.Shuttles.Components;
+
+/// <summary>
+/// Added to players after having been spawned onto the station.
+/// Prevents them from taking the arrivals shuttle.
+/// </summary>
+[RegisterComponent]
+public sealed class ClockedInComponent : Component
+{
+
+}