mobile view enhancement

part of index moved out to header.php
new css/button.css for mobile menu added (from cssbuttongenerator.com)
on mobile (<767px) now vertical button menu
background on mobile removed by code snippet in style.css
css id navmenu-mobile from now on obsolete

pending jobs:
design of desktop menu (and mobile menu)
creation of graphical header
wordpress plugin for Einsätze?
apply changes of index.php also to pages.php
preparing text snippets for page excerpts, review text