Switch to GameActivity and gradle build

Fixes: https://github.com/damus-io/notedeck/issues/189
Fixes: https://github.com/damus-io/notedeck/issues/190
Signed-off-by: William Casarin <jb55@jb55.com>

crates/notedeck_chrome/android/app/build.gradle

@@ -0,0 +1,28 @@
+plugins {
+    id "com.android.application"
+}
+
+android {
+    namespace "com.damus.notedeck"
+    compileSdk 31
+
+    defaultConfig {
+        minSdk 29
+        targetSdk 33
+        versionCode 1
+        versionName "1"
+    }
+
+    buildTypes {
+        debug
+    }
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
+}
+
+dependencies {
+    implementation "com.google.android.material:material:1.5.0"
+    implementation "androidx.games:games-activity:2.0.2"
+}