Updated remove_menu.sh for 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/remove_menu.sh

@@ -17,7 +17,7 @@ remove_ui(){
   echo -e "|  3) [Mainsail]            |  9) [PrettyGCode]         | "
   echo -e "|  4) [Fluidd]              |                           | "
   echo -e "|                           | 10) [NGINX]               | "
-  quit_footer
+  back_footer
 }
 
 remove_menu(){
@@ -45,7 +45,7 @@ remove_menu(){
         do_action "remove_prettygcode" "remove_ui";;
       10)
         do_action "remove_nginx" "remove_ui";;
-      Q|q)
+      B|b)
         clear; main_menu; break;;
       *)
         deny_action "remove_ui";;