serve datastore over the webserver in the example nginx config

docs/example.nginx.conf

@@ -67,6 +67,25 @@ server {
         proxy_set_header Connection upgrade;
     }
 
+    location ^~ /datastore/ {
+        alias /home/cryptpad/office.cryptpad/data/datastore;
+        if ($request_method = 'OPTIONS') {
+            add_header 'Access-Control-Allow-Origin' '*';
+            add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
+            add_header 'Access-Control-Allow-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Content-Range,Range';
+            add_header 'Access-Control-Max-Age' 0;
+            add_header 'Content-Type' 'application/octet-stream; charset=utf-8';
+            add_header 'Content-Length' 0;
+            return 204;
+        }
+        add_header Cache-Control max-age=0;
+        add_header 'Access-Control-Allow-Origin' '*';
+        add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
+        add_header 'Access-Control-Allow-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Content-Range,Range';
+        add_header 'Access-Control-Expose-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Content-Range,Range';
+        try_files $uri =404;
+    }
+
     location ^~ /customize.dist/ {
         # This is needed in order to prevent infinite recursion between /customize/ and the root
     }