Increase the request body size of the /skynet/restore endpoint to 5MB.

docker/nginx/conf.d/server/server.api

@@ -112,6 +112,10 @@ location /skynet/registry {
     include /etc/nginx/conf.d/include/location-skynet-registry;
 }
 
+location /skynet/restore {
+    client_max_body_size 5M;
+}
+
 location /skynet/skyfile {
     include /etc/nginx/conf.d/include/cors;
     include /etc/nginx/conf.d/include/sia-auth;