Support requesting Do Not Disturb access

The respective permission is declared in the manifest
and a shortcut to the respective settings is in the Kõnele developer menu.

It seems that this would only be needed if Kõnele is used
while background audio is playing and the app that plays it
ignores the request to pause it.

Having access to Do Not Disturb setting allows us to mute the audio
stream (on N and higher). This has always seemed to work on the phone,
but crashes on TV if Do Not Disturb access was not granted.

app/build.gradle

@@ -20,8 +20,8 @@ android {
         applicationId 'ee.ioc.phon.android.speak'
         minSdkVersion 16
         targetSdkVersion 29
-        versionCode 1711
-        versionName '1.7.11'
+        versionCode 1712
+        versionName '1.7.12'
     }
 
     compileOptions {

app/src/main/AndroidManifest.xml

@@ -37,6 +37,10 @@
     -->
     <uses-permission android:name="com.android.alarm.permission.SET_ALARM" />
 
+    <!-- TODO: investigate if we need this permission (and enable it during runtime), to
+    mute the audio stream during recognition. -->
+    <uses-permission android:name="android.permission.ACCESS_NOTIFICATION_POLICY" />
+
     <!-- Custom permission required by GetPutPreferenceActivity to be able to read/write the Kõnele settings. -->
     <!--
     <uses-permission android:name="ee.ioc.phon.android.speak.permission.GET_PUT_SETTING" />

app/src/main/res/xml/preferences.xml

@@ -221,6 +221,12 @@
                         android:targetClass="ee.ioc.phon.android.speak.demo.ImeListDemo"
                         android:targetPackage="ee.ioc.phon.android.speak" />
                 </Preference>
+                <!-- TODO: localize -->
+                <Preference
+                    android:summary="Switch on if background audio does not stop during recognition"
+                    android:title="Do Not Disturb access">
+                    <intent android:action="android.settings.NOTIFICATION_POLICY_ACCESS_SETTINGS" />
+                </Preference>
             </PreferenceCategory>
         </PreferenceScreen>
     </PreferenceCategory>