Implement Dark Theme (DayNight with automatic option)

This is just a first rough implementation.
A real UI designer should look over this.

briar-android/src/main/res/drawable/blogs.xml

@@ -1,7 +1,6 @@
 <vector xmlns:android="http://schemas.android.com/apk/res/android"
         android:width="24dp"
         android:height="24dp"
-        android:alpha="0.54"
         android:viewportHeight="24.0"
         android:viewportWidth="24.0">
 	<path