add: notification upon head arrival (#402)

Content.Shared/_White/Announcement/ArrivalNotificationPrototype.cs

@@ -0,0 +1,33 @@
+using Robust.Shared.Prototypes;
+
+namespace Content.Shared._White.Announcement;
+
+[Prototype("arrivalNotification")]
+public sealed partial class ArrivalNotificationPrototype : IPrototype
+{
+    [IdDataField] public string ID { get; } = default!;
+
+    /// <summary>
+    ///     The message that the department will receive upon the player arrival
+    /// </summary>
+    [DataField(required: true)]
+    public string Message = default!;
+
+    /// <summary>
+    ///     The message that the station will receive upon the player arrival
+    /// </summary>
+    [DataField]
+    public string GlobalMessage = default!;
+
+    /// <summary>
+    ///     ID of the channel where the player arrival will be announced.
+    /// </summary>
+    [DataField(required: true)]
+    public HashSet<string> RadioChannelsPrototypes = default!;
+
+    /// <summary>
+    ///     Determines whether the notification will be made to the entire station. If false, the notification will be on the department radio channel
+    /// </summary>
+    [DataField]
+    public bool UseGlobalAnnouncement;
+}