Add round end Discord pings, discord webhook API (#19468)

Content.Server/Discord/WebhookUser.cs

@@ -0,0 +1,58 @@
+using System.Text.Json.Serialization;
+
+namespace Content.Server.Discord;
+
+// https://discord.com/developers/docs/resources/user#user-object
+public struct WebhookUser
+{
+    [JsonPropertyName("id")]
+    public ulong Id { get; set; }
+
+    [JsonPropertyName("username")]
+    public string Username { get; set; }
+
+    [JsonPropertyName("discriminator")]
+    public string Discriminator { get; set; }
+
+    [JsonPropertyName("global_name")]
+    public string? GlobalName { get; set; }
+
+    [JsonPropertyName("avatar")]
+    public string? Avatar { get; set; }
+
+    [JsonPropertyName("bot")]
+    public bool? Bot { get; set; }
+
+    [JsonPropertyName("system")]
+    public bool? System { get; set; }
+
+    [JsonPropertyName("mfa_enabled")]
+    public bool? MfaEnabled { get; set; }
+
+    [JsonPropertyName("banner")]
+    public string? Banner { get; set; }
+
+    [JsonPropertyName("accent_color")]
+    public int? AccentColor { get; set; }
+
+    [JsonPropertyName("locale")]
+    public string? Locale { get; set; }
+
+    [JsonPropertyName("verified")]
+    public bool? Verified { get; set; }
+
+    [JsonPropertyName("email")]
+    public string? Email { get; set; }
+
+    [JsonPropertyName("flags")]
+    public int? Flags { get; set; }
+
+    [JsonPropertyName("premium_type")]
+    public int? PremiumType { get; set; }
+
+    [JsonPropertyName("public_flags")]
+    public int? PublicFlags { get; set; }
+
+    [JsonPropertyName("avatar_decoration")]
+    public string? AvatarDecoration { get; set; }
+}