Round start audio announcement (#8047)

Content.Server/Announcements/RoundAnnouncementPrototype.cs

@@ -0,0 +1,23 @@
+using Content.Server.GameTicking.Presets;
+using Content.Shared.Sound;
+using Robust.Shared.Prototypes;
+using Robust.Shared.Serialization.TypeSerializers.Implementations.Custom.Prototype.List;
+
+namespace Content.Server.Announcements;
+
+/// <summary>
+/// Used for any announcements on the start of a round.
+/// </summary>
+[Prototype("roundAnnouncement")]
+public sealed class RoundAnnouncementPrototype : IPrototype
+{
+    [IdDataFieldAttribute]
+    public string ID { get; } = default!;
+
+    [DataField("sound")] public SoundSpecifier? Sound;
+
+    [DataField("message")] public string? Message;
+
+    [DataField("presets", customTypeSerializer: typeof(PrototypeIdListSerializer<GamePresetPrototype>))]
+    public List<string> GamePresets = new();
+}