Running export_server_packages on atsserver

I'm using the docker image for ats server. When I try to start it, it dies with this message

```
[MP] =========================================================================
*** ERROR *** : [MP] Error: Server packages file not found. This is required to load proper map, DLCs and mods.
*** ERROR *** : [MP] Error: Use "export_server_packages" command in game to export server game settings.
*** ERROR *** : [MP] Error: See server_readme.txt.
*** ERROR *** : [MP] Error: Server was teminated.
[MP] =========================================================================
```

The `server_readme.txt` links to [https://modding.scssoft.com/wiki/Documentation/Tools/Dedicated_Server](https://modding.scssoft.com/wiki/Documentation/Tools/Dedicated_Server#How_to_export_server_packages).

Seems like I need to run this `export_server_packages` in the "console". The doc indicates you do this in steam GUI ("press ~"), but I am putting this on a headless server.

I tried logging into the server console with `docker exec -it atsserver sudo -u linuxgsm ./atsserver console` but that fails because the server has already crashed.