Add support for extraArgs, Update server version

[kmjayadeep]

• Added support for extraArgs parameters. This way we can add arbitrary arguments to the binary. My primary use case was to add world modifiers and global keys, which seems to work really well.
• Also updated the manifest to the latest version. For some reason, the previous version was not getting downloaded from the depot.

I'm already using this patch here: https://github.com/kmjayadeep/homelab-iac/blob/253dc1db0abb54979fed0f74bba8c3095df17e3f/nixos-images/valheim/hosts/chillyfries.nix#L25