Remove libstructure

Migrate to 1.16.2 final

src/main/java/appeng/mixins/feature/ConfiguredFeaturesAccessor.java

@@ -0,0 +1,19 @@
+package appeng.mixins.feature;
+
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.gen.Invoker;
+
+import net.minecraft.world.gen.feature.ConfiguredFeature;
+import net.minecraft.world.gen.feature.ConfiguredFeatures;
+import net.minecraft.world.gen.feature.FeatureConfig;
+
+@Mixin(ConfiguredFeatures.class)
+public interface ConfiguredFeaturesAccessor {
+
+    @Invoker("register")
+    static <FC extends FeatureConfig> ConfiguredFeature<FC, ?> register(String id,
+            ConfiguredFeature<FC, ?> configuredFeature) {
+        throw new AssertionError();
+    }
+
+}