[BUGFIX] removed the wrong style and aria attributes from footer, add bootstrap class "sr-only" (#472)

Author: ajdin99

Resources/Private/Partials/Footer/Footer.html

@@ -9,7 +9,7 @@
 <footer class="footer" role="contentinfo">
 
 	<f:comment>H2 is needed to provide valid HTML structure https://www.w3.org/WAI/tutorials/page-structure/headings/</f:comment>
-	<h2 class="hidden" aria-hidden="true"><f:translate key="footer.firstHeadline" extensionName="theme_t3kit"/></h2>
+	<h2 class="sr-only"><f:translate key="footer.firstHeadline" extensionName="theme_t3kit"/></h2>
 	<f:cObject typoscriptObjectPath="lib.footer" />
 
 </footer>