feat(tyrant): add reign control panel

src/main/java/games/dmg/spigottyrant/TyrantControlPanel.java

@@ -0,0 +1,19 @@
+package games.dmg.spigottyrant;
+
+import java.util.UUID;
+import org.bukkit.entity.Player;
+
+@FunctionalInterface
+public interface TyrantControlPanel {
+    void open(Player player);
+
+    default void beginSession(UUID playerId) {
+    }
+
+    default void endSession(UUID playerId) {
+    }
+
+    default boolean openedThisSession(UUID playerId) {
+        return false;
+    }
+}