Add --arkopt,<option> command-line option

Use `--arkopt,-optname=optval` or `--arkopt,-optname` for dash options.
Use `--arkopt,optname=optval` for options in the server options string.

tools/arkmanager

@@ -2782,6 +2782,28 @@ useConfig() {
   arkupdatelockfile="${arkupdatelockfile:-ShooterGame/Saved/.ark-update.lock}"
 }
 
+addArkOpt() {
+  local optname="${1%%=*}"
+  local optval="${1#*=}"
+  local optdash="${optname:0:1}"
+  
+  optname="${optname#-}"
+  optname="${optname//[^A-Za-z0-9_]/_}"
+  
+  if [[ "${optval}" == "${optname}" ]]; then
+    optval=""
+  fi
+  if [[ "${optdash}" == "-" ]]; then
+    if [[ -z "${optval}" ]]; then
+      IFS="" read -r "arkflag_${optname}" <<<"true"
+    else
+      IFS="" read -r "arkopt_${optname}" <<<"${optval}"
+    fi
+  else
+    IFS="" read -r "ark_${optname}" <<<"${optval}"
+  fi
+}
+
 showUsage() {
   echo -e "Usage: arkmanager [Commands]\n"
   echo "Commands can be followed by one or more @instance arguments"
@@ -2900,6 +2922,9 @@ main(){
         --spinner)
           progressDisplayType=spinner
         ;;
+        --arkopt,*)
+          addArkOpt "${1#--arkopt,}"
+        ;;
         --*)
           options+=( "$1" )
         ;;