Render menu block in twig template
The easiest solution is to make use of twig tweaks module, Install twig tweak 

drush -y en twig_tweak, 
drush cr, 


now you can place navigation anywhere. In your case inside header.twig file place

{{ drupal_block('crmnavigation') }}


You can also render entities, views and many other things. well explained here http://www.wdtutorials.com/drupal/theming/drupal-8-tutorial-43-twig-tweak-module-article-video#.WCPOxeErIyk