refactor: improve conditional statements in install_config.sh

The code changes refactor the conditional statements in the `install_config.sh` file. Instead of checking if `${shortname}` is equal to "dst" or "arma3", it now checks if `${clustercfgdir}` or `${networkcfgdir}` are not empty, respectively. This improves readability and maintainability of the code.

lgsm/modules/install_config.sh

@@ -10,10 +10,10 @@ moduleselfname="$(basename "$(readlink -f "${BASH_SOURCE[0]}")")"
 # Checks if server cfg dir exists, creates it if it doesn't.
 fn_check_cfgdir() {
 	changes=""
-	if [ "${shortname}" == "dst" ]; then
+	if [ -n "${clustercfgdir}" ]; then
 		echo -en "creating config directory [ ${italic}${clustercfgdir}${default} ]"
 		changes+=$(mkdir -pv "${clustercfgdir}")
-	elif [ "${shortname}" == "arma3" ]; then
+	elif [ -n "${networkcfgdir}" ]; then
 		echo -en "creating config directory [ ${italic}${networkcfgdir}${default} ]"
 		changes+=$(mkdir -pv "${networkcfgdir}")
 	else