People Aliases and Merging (#3795)

Co-authored-by: Joseph Milazzo <josephmajora@gmail.com>

API/SignalR/MessageFactory.cs

@@ -1,5 +1,6 @@
 using System;
 using API.DTOs.Update;
+using API.Entities.Person;
 using API.Extensions;
 using API.Services.Plus;
 
@@ -147,6 +148,10 @@ public static class MessageFactory
     /// Volume is removed from server
     /// </summary>
     public const string VolumeRemoved = "VolumeRemoved";
+    /// <summary>
+    /// A Person merged has been merged into another
+    /// </summary>
+    public const string PersonMerged = "PersonMerged";
 
     public static SignalRMessage DashboardUpdateEvent(int userId)
     {
@@ -661,4 +666,17 @@ public static class MessageFactory
             EventType = ProgressEventType.Single,
         };
     }
+
+    public static SignalRMessage PersonMergedMessage(Person dst, Person src)
+    {
+        return new SignalRMessage()
+        {
+            Name = PersonMerged,
+            Body = new
+            {
+                srcId = src.Id,
+                dstName = dst.Name,
+            },
+        };
+    }
 }