appstore: Add gunicorn, systemd, nginx conf snippets for deployment

store/nginx.conf.example

@@ -0,0 +1,15 @@
+location / {
+    try_files $uri @appstore;
+}
+
+location /assets {
+    alias __INSTALL_DIR__/assets/;
+}
+
+location @appstore {
+    proxy_pass http://unix:__INSTALL_DIR__/sock;
+    proxy_set_header Host $host;
+    proxy_set_header X-Real-IP $remote_addr;
+    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+    proxy_set_header X-Forwarded-Proto $scheme;
+}