Wait for the server to shutdown before restoring a backup

[Luatan]

Context

• The restore script does not wait for the server to actually shut down
• Because of this Settings are reverted after the server restarts
• Closes Restoring backup from another server does not work using restore script #359

Choices

• Getting the PID of the PalServer-Linux-Test binary to test if it is still running
• Continue with the restore only after the server has shutdown

Test instructions

1. Start a Server
2. Create a backup
3. Extract the backup and change the id in /palworld/Pal/Saved/Config/LinuxServer/GameUserSettings.ini
4. Rename the directory in /palworld/Pal/Saved/SaveGames/0/ to the ID in GameUserSettings.ini
5. Tar the 'Saved' directory again
6. Run the restore command docker exec -it palworld-server restore
7. Select the backup which was altered
8. Verify that the server has restarted
9. Verify that the ID in GameUserSettings.ini is the same which was used in the backup
10. Verify that the directory in /palworld/Pal/Saved/SaveGames/0/ has the correct name

Checklist before requesting a review

• I have performed a self-review of my code
• I've added documentation about this change to the README.
• I've not introduced breaking changes.