feat(vhserver): added additional config string for valheim world modifiers

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

@@ -22,11 +22,35 @@ backups="4"
 backupshort="7200"
 backuplong="43200"
 # If crossplay is empty, it's off. Fill with any text to make true
-# Crossplay is currently not working on Linux dedicated servers, so for now the default is false (emtpy)
+# Crossplay is currently not working on Linux dedicated servers, so for now the default is false (empty)
 crossplay=""
 
+# INSTRUCTIONS FOR WORLD MODIFIERS (from Valheim Dedicated Server Manual.pdf located in serverfiles)
+# World modifiers can only be set in the start parameters and can be a combination of the following
+# PRESETS:
+# 	Setting a preset will overwrite any other previous modifiers.
+# 	Command line parameter: -preset
+# 	Valid values: normal, casual, easy, hard, hardcore, immersive, hammer.
+# MODIFIERS:
+# 	This is set as a combination of key and value, if combined with a preset should be set after.
+# 	Command line parameter: -modifier
+# 	Valid keys and possible values:
+# 	combat: veryeasy, easy, hard, veryhard
+# 	deathPenalty: casual, veryeasy, easy, hard, hardcore
+# 	resources: muchless, less, more, muchmore, most
+# 	raids: none, muchless, less, more, muchmore
+# 	portals: casual, hard, veryhard
+# KEYS:
+# 	Sets a world modifier checkbox key.
+# 	Command line parameter: -setkey
+# 	Valid values: nobuildcost, playerevents, passivemobs, nomap
+# Example of a cobination of modifiers where we set no raids, very hard portals and no map run:
+# modifiers="-modifier raids none -modifier portals veryhard -setkey nomap"
+
+worldmodifiers=""
+
 ## Server Parameters | https://docs.linuxgsm.com/configuration/start-parameters#additional-parameters
-startparameters="-name '${servername}' -password ${serverpassword} -port ${port} -world ${worldname} -public ${public} -savedir '${savedir}' -logFile '${logFile}' -saveinterval ${saveinterval} -backups ${backups} -backupshort ${backupshort} -backuplong ${backuplong} ${crossplay:+-crossplay}"
+startparameters="-name '${servername}' -password ${serverpassword} -port ${port} -world ${worldname} -public ${public} -savedir '${savedir}' -saveinterval ${saveinterval} -backups ${backups} -backupshort ${backupshort} -backuplong ${backuplong}${logFile:+ -logFile '${logFile}'}${crossplay:+ -crossplay}${worldmodifiers:+ ${worldmodifiers}}"
 
 #### LinuxGSM Settings ####