Add extended PaperServerListPingEvent (#980)

* Drop original implementation for old player sample API

* Add extended PaperServerListPingEvent

Add a new event that extends the original ServerListPingEvent
and allows full control of the response sent to the client.

* Implement deprecated player sample API

Spigot-Server-Patches/0274-Disable-Explicit-Network-Manager-Flushing.patch

@@ -1,37 +0,0 @@
-From b7806469aa14552fea0aece2446419b9a96c27cc Mon Sep 17 00:00:00 2001
-From: Aikar <aikar@aikar.co>
-Date: Sun, 11 Mar 2018 14:13:33 -0400
-Subject: [PATCH] Disable Explicit Network Manager Flushing
-
-This seems completely pointless, as packet dispatch uses .writeAndFlush.
-
-Things seem to work fine without explicit flushing, but incase issues arise,
-provide a System property to re-enable it using improved logic of doing the
-flushing on the netty event loop, so it won't do the flush on the main thread.
-
-Renable flushing by passing -Dpaper.explicit-flush=true
-
-diff --git a/src/main/java/net/minecraft/server/NetworkManager.java b/src/main/java/net/minecraft/server/NetworkManager.java
-index b93a26e8f..da7c45697 100644
---- a/src/main/java/net/minecraft/server/NetworkManager.java
-+++ b/src/main/java/net/minecraft/server/NetworkManager.java
-@@ -78,6 +78,7 @@ public class NetworkManager extends SimpleChannelInboundHandler<Packet<?>> {
-     // Paper start - NetworkClient implementation
-     public int protocolVersion;
-     public java.net.InetSocketAddress virtualHost;
-+    private static boolean enableExplicitFlush = Boolean.getBoolean("paper.explicit-flush");
-     // Paper end
- 
-     public NetworkManager(EnumProtocolDirection enumprotocoldirection) {
-@@ -255,7 +256,7 @@ public class NetworkManager extends SimpleChannelInboundHandler<Packet<?>> {
-         }
- 
-         if (this.channel != null) {
--            this.channel.flush();
-+            if (enableExplicitFlush) this.channel.eventLoop().execute(() -> this.channel.flush()); // Paper - we don't need to explicit flush here, but allow opt in incase issues are found to a better version
-         }
- 
-     }
--- 
-2.16.2
-