Adds admin command to reset all island flags to default

Used when an admin wants to change the default flag settings for all
islands and reset every one in the world.

src/main/java/world/bentobox/bentobox/api/commands/admin/AdminResetFlagsCommand.java

@@ -0,0 +1,37 @@
+package world.bentobox.bentobox.api.commands.admin;
+
+import java.util.List;
+
+import world.bentobox.bentobox.api.commands.CompositeCommand;
+import world.bentobox.bentobox.api.commands.ConfirmableCommand;
+import world.bentobox.bentobox.api.user.User;
+
+/**
+ * Admin command to reset all islands in a world to the default flag setting in the game mode config.yml
+ * @author tastybento
+ * @since 1.3.0
+ */
+public class AdminResetFlagsCommand extends ConfirmableCommand {
+
+    public AdminResetFlagsCommand(CompositeCommand parent) {
+        super(parent, "resetflags");
+    }
+
+    @Override
+    public void setup() {
+        setPermission("admin.resetflags");
+        setOnlyPlayer(false);
+        setDescription("commands.admin.resetflags.description");
+    }
+
+    @Override
+    public boolean execute(User user, String label, List<String> args) {
+        // Everything's fine, we can set the island as spawn :)
+        askConfirmation(user, () -> {
+            getIslands().resetAllFlags(getWorld());
+            user.sendMessage("general.success");
+        });
+        return true;
+    }
+
+}

src/main/java/world/bentobox/bentobox/managers/IslandsManager.java

@@ -940,4 +940,14 @@ public class IslandsManager {
     public Optional<Island> getIslandById(String uniqueId) {
         return Optional.ofNullable(islandCache.getIslandById(uniqueId));
     }
+
+    /**
+     * Resets all flags to gamemode config.yml default
+     * @param world - world
+     * @since 1.3.0
+     */
+    public void resetAllFlags(World world) {
+        islandCache.resetAllFlags(world);
+        this.saveAll();
+    }
 }

src/main/java/world/bentobox/bentobox/managers/island/IslandCache.java

@@ -22,6 +22,9 @@ import world.bentobox.bentobox.util.Util;
 public class IslandCache {
     @NonNull
     private Map<@NonNull Location, @NonNull Island> islandsByLocation;
+    /**
+     * Map of all islands with island uniqueId as key
+     */
     @NonNull
     private Map<@NonNull String, @NonNull Island> islandsById;
     /**
@@ -262,4 +265,14 @@ public class IslandCache {
     public Island getIslandById(String uniqueId) {
         return islandsById.get(uniqueId);
     }
+
+    /**
+     * Resets all islands in this game mode to default flag settings
+     * @param world - world
+     * @since 1.3.0
+     */
+    public void resetAllFlags(World world) {
+        World w = Util.getWorld(world);
+        islandsById.values().stream().filter(i -> i.getWorld().equals(w)).forEach(i -> i.setFlagsDefaults());
+    }
 }

src/main/resources/locales/en-US.yml

@@ -197,6 +197,8 @@ commands:
       save:
         parameters: "<schem name>"
         description: "save the copied clipboard"      
+    resetflags:
+      description: "Reset all islands to default flag settings in config.yml"
     world:
       description: "Manage world settings"
     delete: