LZ-17: Add initial block restore queue registry, and a registration event

src/main/java/dev/zontreck/libzontreck/memory/world/BlockRestoreQueueRegistry.java

@@ -0,0 +1,21 @@
+package dev.zontreck.libzontreck.memory.world;
+
+import java.util.*;
+
+/**
+ * DANGER: DO NOT USE THIS CLASS DIRECTLY
+ */
+public class BlockRestoreQueueRegistry
+{
+    private static Map<String, BlockRestoreQueue> QUEUES = new HashMap<>();
+
+    /**
+     * Internal use only
+     *
+     * @see dev.zontreck.libzontreck.events.BlockRestoreQueueRegistrationEvent
+     * @param queue The queue to register
+     */
+    public static void addQueue(BlockRestoreQueue queue) {
+        QUEUES.put(queue.getRestoreQueueName(), queue);
+    }
+}