Updated settings_menu.sh to have a back_footer

When I first ran the code, I went to advanced because I had klipper already installed and I wanted to see if I could install fluidd using this code base.
So when see advanced menu I was concerned that "quit" meant quitting the tool instead of exiting the advanced menu. So proposing a back_footer for sub menus that will revert back to main menu. Save quit footer for main menu to exit program.

scripts/ui/settings_menu.sh

@@ -20,7 +20,7 @@ settings_ui(){
   else
   echo -e "|  1) Change config folder                              | "
   fi
-  quit_footer
+  back_footer
 }
 
 settings_menu(){
@@ -34,7 +34,7 @@ settings_menu(){
         else
           deny_action "settings_ui"
         fi;;
-      Q|q)
+      B|b)
         clear; main_menu; break;;
       *)
         deny_action "settings_ui";;