Separated libpupil to standalone repository

Migrated to Kotlin 1.4

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

@@ -18,6 +18,7 @@
   -->
 
 <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
     xmlns:app="http://schemas.android.com/apk/res-auto"
@@ -44,6 +45,7 @@
         app:tint="?attr/colorControlNormal"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintTop_toTopOf="parent"
-        app:layout_constraintBottom_toBottomOf="parent"/>
+        app:layout_constraintBottom_toBottomOf="parent"
+        tools:ignore="ContentDescription" />
 
 </androidx.constraintlayout.widget.ConstraintLayout>