fix:(vhserver) Add support for changing savedir in valheim (#3266)

lgsm/config-default/config-lgsm/vhserver/_default.cfg

@@ -15,9 +15,10 @@ serverpassword=""
 port="2456"
 gameworld="${selfname}"
 public="1"
+savedir="$HOME/.config/unity3d/IronGate/Valheim"
 
 ## Server Parameters | https://docs.linuxgsm.com/configuration/start-parameters#additional-parameters
-startparameters="-name '${servername}' -password ${serverpassword} -port ${port} -world ${gameworld} -public ${public}"
+startparameters="-name '${servername}' -password ${serverpassword} -port ${port} -world ${gameworld} -public ${public} -savedir '${savedir}'"
 
 #### LinuxGSM Settings ####