Add support for AndroidX preferences (#1971)

* Add stubs for AndroidX preferences

* Update extensions for AndroidX preferences

lib/preference-stub/src/main/java/androidx/preference/Preference.java

@@ -0,0 +1,49 @@
+package androidx.preference;
+
+public class Preference {
+
+    public void setOnPreferenceChangeListener(OnPreferenceChangeListener onPreferenceChangeListener) {
+        throw new RuntimeException("Stub!");
+    }
+
+    public void setOnPreferenceClickListener(OnPreferenceClickListener onPreferenceClickListener) {
+        throw new RuntimeException("Stub!");
+    }
+
+    public CharSequence getTitle() {
+        throw new RuntimeException("Stub!");
+    }
+
+    public void setTitle(CharSequence title) {
+        throw new RuntimeException("Stub!");
+    }
+
+    public CharSequence getSummary() {
+        throw new RuntimeException("Stub!");
+    }
+
+    public void setSummary(CharSequence summary) {
+        throw new RuntimeException("Stub!");
+    }
+
+    public String getKey() {
+        throw new RuntimeException("Stub!");
+    }
+
+    public void setKey(String key) {
+        throw new RuntimeException("Stub!");
+    }
+
+    public void setDefaultValue(Object defaultValue) {
+        throw new RuntimeException("Stub!");
+    }
+
+    public interface OnPreferenceChangeListener {
+        boolean onPreferenceChange(Preference preference, Object newValue);
+    }
+
+    public interface OnPreferenceClickListener {
+        boolean onPreferenceClick(Preference preference);
+    }
+
+}