[fix] XPath engine azlyrics - new parameter x is needed.

This commit adds a static `x` argument to the GET URL.  Its not clear how long
this static value will work.  The alternative is to implement a python modul for
this engine to get the `x` argument from the HTML form of

https://search.azlyrics.com/search.php / the XPath selector to get the value is::

        //input[@name='x']@value

Closes: searxng#3280
Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

searx/settings.yml

@@ -1093,7 +1093,7 @@ engines:
     disabled: true
     categories: [music, lyrics]
     paging: true
-    search_url: https://search.azlyrics.com/search.php?q={query}&w=lyrics&p={pageno}
+    search_url: https://search.azlyrics.com/search.php?q={query}&w=lyrics&p={pageno}&x=7f889302d4f34f629e1fc4adbdd48e67b4e7c6c2cdf3add48438b16b5299d2cb
     url_xpath: //td[@class="text-left visitedlyr"]/a/@href
     title_xpath: //span/b/text()
     content_xpath: //td[@class="text-left visitedlyr"]/a/small