style: improve code-style and fix some shellcheck warnings

Signed-off-by: Dominik Willner th33xitus@gmail.com

scripts/ui/advanced_menu.sh

@@ -28,6 +28,8 @@ function advanced_ui() {
 
 function advanced_menu() {
   do_action "" "advanced_ui"
+
+  local action
   while true; do
     read -p "${cyan}####### Perform action:${white} " action
     case "${action}" in