Cache the last 3 rounds of admin logs in memory

Reduces send logs time from 2/10/45 seconds to 2 milliseconds
Not thread safe
Removes LogRecord

Content.Server/GameTicking/Events/RoundStartingEvent.cs

@@ -3,7 +3,7 @@
 namespace Content.Server.GameTicking.Events;
 
 /// <summary>
-///     Raised at the start of <see cref="GameTicker.StartRound"/>
+///     Raised at the start of <see cref="GameTicker.StartRound"/>, after round id has been incremented
 /// </summary>
 public class RoundStartingEvent : EntityEventArgs
 {