Client customization late-join spawner priority for arrivals/cryostorage (#24586)

* Initial commit, requires server restart to take effect

* Exposes callbacks directly instead, takes effect immediately

* Cleaned up control flow, swapped cvar for client customization

* Switched to int, dictionary of callbacks, migration

* Update Content.Shared/Preferences/SpawnPriorityPreference.cs

* krunkle stan

---------

Co-authored-by: metalgearsloth <31366439+metalgearsloth@users.noreply.github.com>
Co-authored-by: metalgearsloth <comedian_vs_clown@hotmail.com>

Content.Shared/Preferences/SpawnPriorityPreference.cs

@@ -0,0 +1,15 @@
+namespace Content.Shared.Preferences
+{
+    /// <summary>
+    /// The spawn priority preference for a profile. Stored in database!
+    /// </summary>
+    public enum SpawnPriorityPreference
+    {
+        ///////////////////////
+        /// DO NOT TOUCH!!! ///
+        ///////////////////////
+        None = 0,
+        Arrivals = 1,
+        Cryosleep = 2,
+    }
+}