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.IntegrationTests/Tests/Administration/Logs/QueryTests.cs

@@ -59,7 +59,7 @@ public class QueryTests : ContentIntegrationTest
 
         await WaitUntil(server, async () =>
         {
-            await foreach (var _ in sAdminLogSystem.All(filter))
+            foreach (var _ in await sAdminLogSystem.All(filter))
             {
                 return true;
             }