Added new plugin.yml option 'load', possible values are 'startup' and 'postworld' (default postworld)

By: Dinnerbone <dinnerbone@dinnerbone.com>

paper-api/src/main/java/org/bukkit/plugin/PluginLoadOrder.java

@@ -0,0 +1,16 @@
+
+package org.bukkit.plugin;
+
+/**
+ * Represents the order in which a plugin should be initialized and enabled
+ */
+public enum PluginLoadOrder {
+    /**
+     * Indicates that the plugin will be loaded at startup
+     */
+    STARTUP,
+    /**
+     * Indicates that the plugin will be loaded after the first/default world was created
+     */
+    POSTWORLD
+}