Improvements for docker documentation

(cherry picked from commit a619e92ca8946c336116dfd0cb1e5ef4cb3c9588)

_includes/nginx.conf

@@ -0,0 +1,24 @@
+upstream inventree {
+    # Should point to the InvenTree web server container
+    server web:8000;
+}
+
+server {
+
+    # Listen for connection on (internal) port 80
+    listen 80;
+
+    location / {
+        proxy_pass http://inventree;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        proxy_set_header Host $host;
+        proxy_redirect off;
+        client_max_body_size 100M;
+    }
+
+    # Redirect any requests for static files
+    location /static/ {
+        alias /var/www/static/;
+    }
+
+}