fix(core): Fixes flow for saves, adds logging and configurations (#513)

- [X] Adds better diagnostics for world saves.
- [X] Adds world save stats.
- [X] World now saves to a temporary folder.
- [X] Backups are now stored by timestamp.
- [X] Backup is now made after the world save.
- [X] "Saves" folder is now configurable.
- [X] Temporary folder is now configurable.
- [X] Backups folder is now configurable.

Projects/Server/World/WorldEvents.cs

@@ -0,0 +1,33 @@
+using System;
+using System.Runtime.CompilerServices;
+
+namespace Server
+{
+    public class WorldSavePostSnapshotEventArgs
+    {
+        public string OldSavePath { get; }
+        public string NewSavePath { get; }
+
+        public WorldSavePostSnapshotEventArgs(string oldSavePath, string newSavePath)
+        {
+            OldSavePath = oldSavePath;
+            NewSavePath = newSavePath;
+        }
+    }
+
+    public static partial class EventSink
+    {
+        public static event Action WorldLoad;
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static void InvokeWorldLoad() => WorldLoad?.Invoke();
+
+        public static event Action WorldSave;
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static void InvokeWorldSave() => WorldSave?.Invoke();
+
+        public static event Action<WorldSavePostSnapshotEventArgs> WorldSavePostSnapshot;
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static void InvokeWorldSavePostSnapshot(string oldSavePath, string newSavePath) =>
+            WorldSavePostSnapshot?.Invoke(new WorldSavePostSnapshotEventArgs(oldSavePath, newSavePath));
+    }
+}