feat: add rest client to get gateway url

src/StevesBot.Worker/Discord/DiscordRestClientException.cs

@@ -0,0 +1,16 @@
+namespace StevesBot.Worker.Discord;
+
+internal class DiscordRestClientException : Exception
+{
+  public DiscordRestClientException()
+  {
+  }
+
+  public DiscordRestClientException(string message) : base(message)
+  {
+  }
+
+  public DiscordRestClientException(string message, Exception innerException) : base(message, innerException)
+  {
+  }
+}