Introduce realtime log viewer

This contains a share button and a save button, the former using a
custom content provider.

Co-authored-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Harsh Shandilya <me@msfjarvis.dev>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

ui/src/main/res/menu/log_viewer.xml

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="utf-8"?>
+<menu xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto">
+    <item
+        android:id="@+id/save_log"
+        android:icon="@drawable/ic_action_save"
+        android:title="@string/log_export_title"
+        app:showAsAction="ifRoom"/>
+</menu>