title: Get environment variable in shared razor template
body: <p>I want to change my razor layout depending on a environment variable.</p>
  
  <p>What is the best way to get an environment variable available in a shared _layout.cshtml file so I can change the layout depending on that variable?</p>
  
  <p>Probably I need some dependency injection, but I am not sure how to do this.</p>
  
  <p>Thanks</p>