update dtos for moderator and banned users in groups

MareSynchronosAPI/BannedGroupUserDto.cs

@@ -0,0 +1,16 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace MareSynchronos.API
+{
+    public record BannedGroupUserDto
+    {
+        public string UID { get; set; }
+        public string Reason { get; set; }
+        public DateTime BannedOn { get; set; }
+        public string BannedBy { get; set; }
+    }
+}