NGINX: Increase timeouts

nixos/modules/issuer.nix

@@ -214,6 +214,14 @@ in {
           # we pass less scanning spam on to our backend
           # Want a regex instead? try locations."~ /v\d+/"
           proxyPass = "http://127.0.0.1:${internalHttpPort}";
+
+          # Up the proxy timeouts from the default of 60s
+          # (don't hang up before receiving our client's ZKAPs)
+          extraConfig = ''
+            proxy_read_timeout 600s;
+            proxy_send_timeout 600s;
+            keepalive_timeout 600s;
+          '';
         };
         locations."/metrics" = {
           # Only allow our monitoringvpn subnet