Add new options to screensaver (#3535)

* Prevent open screensaver more than one in the same time

* Add option to enable/disable background in message screensaver

* fallback to random images if this book cover is excluded feature + fix Disabled (leave screen/page as it is)

* Autostretch disable by default, more fallback options, leave screen as it is

frontend/ui/widget/inputtext.lua

@@ -72,8 +72,10 @@ end
 
 function InputText:init()
     self:initTextBox(self.text)
-    self:initKeyboard()
-    self:initEventListener()
+    if self.readonly ~= true then
+        self:initKeyboard()
+        self:initEventListener()
+    end
 end
 
 function InputText:initTextBox(text, char_added, is_password_type)