Add config option for displayname in quit message (#5260)

This restores the behaviour to vanilla by default, but may be changed if
one wants to.

Fixes #5259.

Spigot-Server-Patches/Default-loading-permissions.yml-before-plugins.patch

@@ -20,8 +20,8 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 --- 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 {
-                 " - Length: " + timeSummary(Timings.getHistoryLength() / 20) +
-                 " - Server Name: " + timingsServerName);
+     private static void useDisplayNameInQuit() {
+         useDisplayNameInQuit = getBoolean("use-display-name-in-quit-message", useDisplayNameInQuit);
      }
 +
 +    public static boolean loadPermsBeforePlugins = true;