Adapt System UI colour in light and dark themes (EXPOSUREAPP-6991) (#3078)

* Light navigation bar flag

* Adapt status bar

Corona-Warn-App/src/main/res/values-night/bools.xml

+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <bool name="lightSystemUI">false</bool>
+</resources>
\ No newline at end of file

Corona-Warn-App/src/main/res/values-night/colors.xml

@@ -13,6 +13,7 @@
     <color name="colorSurface2">#434445</color>
     <color name="colorSurface2Pressed">#565757</color>
     <color name="colorHairline">#4DFFFFFF</color>
+    <color name="colorSystemUI">#000000</color>
 
     <!-- Text -->
     <color name="colorTextPrimary1">#FFFFFF</color>

Corona-Warn-App/src/main/res/values/bools.xml

+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <bool name="lightSystemUI">true</bool>
+</resources>
\ No newline at end of file

Corona-Warn-App/src/main/res/values/colors.xml

@@ -15,6 +15,7 @@
     <color name="colorHairline">#3317191A</color>
 
     <color name="cwaGrayHighlight">#5D6F80</color>
+    <color name="colorSystemUI">#F5F5F5</color>
 
     <!--Cards-->
     <color name="colorCardBackgroundHighlightGray">@color/cwaGrayHighlight</color>

Corona-Warn-App/src/main/res/values/styles.xml

-<resources xmlns:android="http://schemas.android.com/apk/res/android">
+<resources xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools">
 
     <style name="AppTheme" parent="Theme.MaterialComponents.DayNight.Bridge">
         <item name="colorPrimary">@color/colorBrandSecondary</item>
@@ -11,6 +11,13 @@
         <item name="materialTimePickerTheme">@style/ThemeOverlay.App.TimePicker</item>
 
         <item name="buttonStyle">@style/Widget.AppCompat.Button.Borderless.Colored</item>
+
+        <item name="android:windowLightNavigationBar" tools:targetApi="o_mr1">@bool/lightSystemUI
+        </item>
+        <item name="android:windowLightStatusBar">@bool/lightSystemUI</item>
+
+        <item name="android:navigationBarColor">@color/colorSystemUI</item>
+        <item name="android:statusBarColor">@color/colorSystemUI</item>
     </style>
 
     <style name="ThemeOverlay.App.DatePicker" parent="ThemeOverlay.MaterialComponents.MaterialCalendar">