Add max-player-auto-save-per-tick setting to spread out saves more

This will force the saves to spread over multiple ticks even when many
players auto save interval is aligned, avoiding spikes on large servers.

Closes #1021

Spigot-Server-Patches/Add-option-to-remove-invalid-statistics.patch

@@ -5,12 +5,12 @@ Subject: [PATCH] Add option to remove invalid statistics
 
 
 diff --git a/src/main/java/com/destroystokyo/paper/PaperConfig.java b/src/main/java/com/destroystokyo/paper/PaperConfig.java
-index da0984a35..28917f63d 100644
+index 459c86bce..ea6fcb39f 100644
 --- a/src/main/java/com/destroystokyo/paper/PaperConfig.java
 +++ b/src/main/java/com/destroystokyo/paper/PaperConfig.java
 @@ -0,0 +0,0 @@ public class PaperConfig {
-     private static void playerAutoSaveRate() {
-         playerAutoSaveRate = getInt("settings.player-auto-save-rate", -1);
+             maxPlayerAutoSavePerTick = (playerAutoSaveRate == -1 || playerAutoSaveRate > 100) ? 10 : 20;
+         }
      }
 +
 +    public static boolean removeInvalidStatistics = false;