[BUG] Valheim backup doesn't backup the worlds

## User Story

After doing a few backups of my server, I checked the contents of the tarballs and noticed that they don't actually contain the worlds, which are by default located in ~/.config/.

## Basic info

* **Distro:** Centos
* **Game:** Valheim
* **Command:** [Backup]
* **LinuxGSM version:** [latest]

## To Reproduce

Steps to reproduce the behaviour:
1. Run `./vhserver backup`
2. Run `tar -tf `
3. Notice the lack of world files

## Expected behaviour

Expected for the worlds to be listed.

I assume this can be fixed by changing the save location to be inside the server files directory, but saving the worlds regardless of save directory should be the default behaviour.