Move Duktape stub to extensions-lib (#9954)

* Move Duktape stub to extensions-lib

* Formatting fixes

* Address build errors

lib/duktape-stub/build.gradle.kts

@@ -1,16 +0,0 @@
-plugins {
-    java
-}
-
-sourceSets {
-    main {
-        java {
-            srcDirs(listOf("src"))
-        }
-    }
-}
-
-java {
-    sourceCompatibility = JavaVersion.VERSION_1_8
-    targetCompatibility = JavaVersion.VERSION_1_8
-}

lib/duktape-stub/src/com/squareup/duktape/Duktape.java

@@ -1,26 +0,0 @@
-package com.squareup.duktape;
-
-import java.io.Closeable;
-import java.io.IOException;
-
-@SuppressWarnings("all")
-public class Duktape implements Closeable {
-
-    public static Duktape create() {
-        throw new RuntimeException("Stub!");
-    }
-
-    @Override
-    public synchronized void close() throws IOException {
-        throw new RuntimeException("Stub!");
-    }
-
-    public synchronized Object evaluate(String script) {
-        throw new RuntimeException("Stub!");
-    }
-
-    public synchronized <T> void set(String name, Class<T> type, T object) {
-        throw new RuntimeException("Stub!");
-    }
-
-}