Add drupal 8 example to make laradock framework agnostic.

nginx/sites/framework-examples/drupal_8.conf

+server {
+    listen 80;
+    listen [::]:80;
+
+    server_name  site_a.dev;
+    root /var/www/site_a;
+    index index.php;
+
+
+    location / {
+        try_files $uri $uri/ /index.php?q=$uri&$args;
+    }
+
+    error_page 404 /404.html;
+    error_page 500 502 503 504 /50x.html;
+    location = /50x.html {
+          root /var/www/site_a;
+    }
+
+    location ~ [^/]\.php(/|$) {
+        fastcgi_split_path_info ^(.+?\.php)(/.*)$;
+        if (!-f $document_root$fastcgi_script_name) {
+            return 404;
+        }
+
+        fastcgi_pass php-upstream;
+        fastcgi_index index.php;
+        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
+        include fastcgi_params;
+    }
+}
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