breaking: only support androidx (#1052)

* GH-841 only support androix

bin/templates/project/AndroidManifest.xml

@@ -35,7 +35,7 @@
         <activity android:name="__ACTIVITY__"
                 android:label="@string/activity_name"
                 android:launchMode="singleTop"
-                android:theme="@android:style/Theme.DeviceDefault.NoActionBar"
+                android:theme="@style/Theme.AppCompat.NoActionBar"
                 android:windowSoftInputMode="adjustResize"
                 android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|smallestScreenSize|screenLayout|uiMode">
             <intent-filter android:label="@string/launcher_name">

bin/templates/project/app/build.gradle

@@ -339,6 +339,7 @@ android {
 
 dependencies {
     implementation fileTree(dir: 'libs', include: '*.jar')
+    implementation 'androidx.appcompat:appcompat:1.2.0'
 
     if (cdvHelpers.getConfigPreference('GradlePluginKotlinEnabled', 'false').toBoolean()) {
         implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"