move x-content-type header to .htaccess

.htaccess

 Header set Strict-Transport-Security "max-age=63072000"
 Header set X-Frame-Options "SAMEORIGIN"
+Header set X-Content-Type-Options "nosniff"

source/layouts/layout.erb

@@ -4,7 +4,6 @@
     <meta charset="utf-8">
     <meta http-equiv="x-ua-compatible" content="ie=edge">
     <meta http-equiv="x-ua-compatible" content="ie=edge">
-    <meta http-equiv="X-Content-Type-Options" content="nosniff">
     <meta http-equiv="X-XSS-Protection" content="1; mode=block">
     <meta http-equiv="Content-Security-Policy" content="default-src 'self'; font-src 'self' fonts.gstatic.com; style-src 'self' fonts.googleapis.com; img-src 'self' learn.totem-project.org;">
     <meta name="viewport"