feat(ui): add spectrum analyzer visualizer

app/src/main/res/layout/preference_visualizer.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical">
+
+    <FrameLayout
+        android:id="@+id/visualizer_container"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:background="#FF000000" />
+
+</LinearLayout>

app/src/main/res/navigation/nav_graph_main.xml

@@ -23,6 +23,9 @@
         <action
             android:id="@+id/action_settings_to_equalizer"
             app:destination="@id/equalizer_destination" />
+        <action
+            android:id="@+id/action_settings_to_visualizer"
+            app:destination="@id/visualizer_destination" />
     </fragment>
 
     <!-- EQUALIZER -->
@@ -31,4 +34,9 @@
         android:name="com.michatec.radio.EqualizerFragment"
         android:label="Equalizer" />
 
+    <!-- VISUALIZER -->
+    <fragment
+        android:id="@+id/visualizer_destination"
+        android:name="com.michatec.radio.VisualizerFragment"
+        android:label="Visualizer" />
 </navigation>

app/src/main/res/values-de/strings.xml

@@ -145,4 +145,5 @@
     <string name="pref_preset_pop">Pop</string>
     <string name="pref_preset_jazz">Jazz</string>
     <string name="pref_preset_flat">Flach</string>
+    <string name="pref_visualizer_title">Spektrumanzeige</string>
 </resources>

app/src/main/res/values/strings.xml

@@ -173,4 +173,5 @@
     <!-- Extras -->
     <string name="loading">Loading...</string>
     <string name="media_route_menu_title">Cast</string>
+    <string name="pref_visualizer_title">Spectrum Analyzer</string>
 </resources>