Migrate gradle scripts to have multiple modules and source sets. Using Kotlin-DSL for enhanced script debugging.

Signed-off-by: Gabriel Harris-Rouquette <gabizou@me.com>

sponge/src/main/java/com/gmail/nossr50/SpongePlugin.java

@@ -0,0 +1,22 @@
+package com.gmail.nossr50;
+
+import org.spongepowered.api.event.Listener;
+import org.spongepowered.api.event.game.state.GamePreInitializationEvent;
+import org.spongepowered.api.plugin.Plugin;
+
+@Plugin(
+    id = "mcmmo",
+    authors = {"nossr50", "gabizou", "bloodmage"},
+    version = "2.2.0-SNAPSHOT",
+    name = "mcMMO",
+    url = "https://www.mcmmo.org/"
+)
+public class SpongePlugin {
+
+
+    @Listener
+    public void onGamePreInit(GamePreInitializationEvent event) {
+
+    }
+
+}