Move version command update checking to the implementation

This makes it easier for downstream projects (forks) to replace the
version fetching system with their own. It is as simple as implementing
an interface and overriding the default implementation of
org.bukkit.UnsafeValues#getVersionFetcher()

It also makes it easier for us to organize things like the version
history feature.

Lastly I have updated the paper implementation to check against the site
API rather than against jenkins.

Spigot-API-Patches/Provide-Chunk-Coordinates-as-a-Long-API.patch

@@ -7,7 +7,7 @@ Allows you to easily access the chunks X/z as a long, and a method
 to look up by the long key too.
 
 diff --git a/src/main/java/org/bukkit/Chunk.java b/src/main/java/org/bukkit/Chunk.java
-index e583f86d..7302b6e3 100644
+index aab292e1..fe77e33a 100644
 --- a/src/main/java/org/bukkit/Chunk.java
 +++ b/src/main/java/org/bukkit/Chunk.java
 @@ -0,0 +0,0 @@ public interface Chunk {
@@ -44,7 +44,7 @@ index e583f86d..7302b6e3 100644
       * Gets the world containing this chunk
       *
 diff --git a/src/main/java/org/bukkit/World.java b/src/main/java/org/bukkit/World.java
-index 3f934c80..dd0ab741 100644
+index 0b328315..32be5210 100644
 --- a/src/main/java/org/bukkit/World.java
 +++ b/src/main/java/org/bukkit/World.java
 @@ -0,0 +0,0 @@ public interface World extends PluginMessageRecipient, Metadatable {