a11y file browser items

Signed-off-by: Andy Scherzinger <info@andy-scherzinger.de>

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

@@ -53,6 +53,7 @@
         android:layout_height="16dp"
         android:layout_below="@id/file_icon"
         android:layout_alignStart="@+id/file_icon"
+        android:contentDescription="@string/encrypted"
         android:src="@drawable/ic_lock_grey600_24px" />
 
     <TextView

app/src/main/res/values/strings.xml

@@ -369,6 +369,7 @@
     <string name="nc_phone_book_integration_account_not_found">Account not found</string>
 
     <string name="starred">Favorite</string>
+    <string name="encrypted">Encrypted</string>
     <string name="password_protected">Password protected</string>
 
     <string name="avatar">Avatar</string>