Adds fire/air alarms (#5018)

Co-authored-by: Vera Aguilera Puerto <6766154+Zumorica@users.noreply.github.com>
Co-authored-by: E F R <602406+Efruit@users.noreply.github.com>
Co-authored-by: metalgearsloth <31366439+metalgearsloth@users.noreply.github.com>
Co-authored-by: metalgearsloth <comedian_vs_clown@hotmail.com>

Content.Shared/Atmos/Monitor/Components/SharedFireAlarmComponent.cs

@@ -0,0 +1,12 @@
+using System;
+using Robust.Shared.Serialization;
+
+namespace Content.Shared.Atmos.Monitor.Components
+{
+    [Serializable, NetSerializable]
+    public enum FireAlarmWireStatus
+    {
+        Power,
+        Alarm
+    }
+}