Add shortcut to global search query from library (closes #2183)

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

@@ -1,6 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent">
 
@@ -14,7 +15,8 @@
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:background="@color/pale_green"
-            android:visibility="gone">
+            android:visibility="gone"
+            tools:visibility="visible">
 
             <TextView
                 android:layout_width="wrap_content"
@@ -26,6 +28,17 @@
 
         </FrameLayout>
 
+        <Button
+            android:id="@+id/btn_global_search"
+            style="@style/Theme.Widget.Button"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:layout_margin="8dp"
+            android:textAllCaps="false"
+            android:visibility="gone"
+            tools:text="Search"
+            tools:visibility="visible" />
+
         <androidx.viewpager.widget.ViewPager
             android:id="@+id/library_pager"
             android:layout_width="match_parent"