Ladybird/Meta: Add Android build

Build an Android APK file that, when configured properly in Qt Creator,
can be used to deploy the browser to an Android device.

The current build requires NDK 24, targets no less than Android API 30,
and Qt Creator 6.4.0.

Ladybird/android/build.gradle

@@ -0,0 +1,81 @@
+buildscript {
+    repositories {
+        google()
+        mavenCentral()
+    }
+
+    dependencies {
+        classpath 'com.android.tools.build:gradle:7.0.2'
+    }
+}
+
+repositories {
+    google()
+    mavenCentral()
+}
+
+apply plugin: 'com.android.application'
+
+dependencies {
+    implementation fileTree(dir: 'libs', include: ['*.jar', '*.aar'])
+}
+
+android {
+    /*******************************************************
+     * The following variables:
+     * - androidBuildToolsVersion,
+     * - androidCompileSdkVersion
+     * - qtAndroidDir - holds the path to qt android files
+     *                   needed to build any Qt application
+     *                   on Android.
+     *
+     * are defined in gradle.properties file. This file is
+     * updated by QtCreator and androiddeployqt tools.
+     * Changing them manually might break the compilation!
+     *******************************************************/
+
+    compileSdkVersion androidCompileSdkVersion.toInteger()
+    buildToolsVersion androidBuildToolsVersion
+    ndkVersion androidNdkVersion
+
+    // Extract native libraries from the APK
+    packagingOptions.jniLibs.useLegacyPackaging true
+
+    sourceSets {
+        main {
+            manifest.srcFile 'AndroidManifest.xml'
+            java.srcDirs = [qtAndroidDir + '/src', 'src', 'java']
+            aidl.srcDirs = [qtAndroidDir + '/src', 'src', 'aidl']
+            res.srcDirs = [qtAndroidDir + '/res', 'res']
+            resources.srcDirs = ['resources']
+            renderscript.srcDirs = ['src']
+            assets.srcDirs = ['assets']
+            jniLibs.srcDirs = ['libs']
+       }
+    }
+
+    tasks.withType(JavaCompile) {
+        options.incremental = true
+    }
+
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
+
+    lintOptions {
+        abortOnError false
+    }
+
+    // Do not compress Qt binary resources file
+    aaptOptions {
+        noCompress 'rcc'
+    }
+
+    defaultConfig {
+        resConfig "en"
+        minSdkVersion qtMinSdkVersion
+        targetSdkVersion qtTargetSdkVersion
+        ndk.abiFilters = qtTargetAbiList.split(",")
+    }
+}