Add support for detecting and chainloading EFI images in /MultiOS-USB/tools/* (#61)

* Add support for detecting and chainloading EFI images in /ISOs/*

* Delete config/efi-images/efi-images.cfg

* Add submenu for EFI User Tools

---------

Co-authored-by: MexIT <25229673+Mexit@users.noreply.github.com>

Author: tuckertwo

config/grub.config

@@ -197,6 +197,29 @@ if [ "${grub_platform}" == "efi" ]; then
 		fi
 	}
 
+	submenu "EFI User Tools -->" {
+		set found=0
+
+		for efifile in /MultiOS-USB/tools/*.efi; do
+			if [ -f "$efifile" ]; then
+				set found=1
+				regexp --set=efiname "/MultiOS-USB/tools/(.*)" "$efifile"
+
+				menuentry --class=efi "$efiname" "$efifile" {
+					chainloader "${2}"
+				}
+			fi
+		done
+
+		if [ "$found" = "0" ]; then
+			menuentry "(!) No .efi files found — place them in /MultiOS-USB/tools/" --class=warning {
+				echo "No EFI files found in /MultiOS-USB/tools/"
+				echo "Copy your .efi files to that folder and reboot."
+				sleep 5
+			}
+		fi
+	}
+
 	submenu "Network bootable OS installers (DHCP) -->" {
 		if net_bootp; then
 			source /MultiOS-USB/config/grub_netboot/main.cfgnet