Remove unnecessary lines in grub conf

iso/boot/ubuntu/grub.cfg

@@ -11,21 +11,11 @@ fi
 
 set timeout=6
 
-if background_image /boot/grub/themes/dappnode/splash.png; then
-  set color_normal=light-gray/black
-  set color_highlight=white/black
-else
-  set menu_color_normal=cyan/blue
-  set menu_color_highlight=white/blue
-fi
-
-insmod play
-play 960 440 1 0 4 440 1 # Plays sound
-set theme=/boot/grub/themes/dappnode
+set theme=/boot/grub/themes/dappnode/theme.txt
 
 menuentry "Install Dappnode (over Ubuntu Server)" {
-        set background_color=black
-        set gfxpayload=keep # Maintain the graphical resolution through the booting
-        linux   /casper/vmlinuz autoinstall vga=788 FRONTEND_BACKGROUND=dark --- # Added autoinstall to make it unattended
-        initrd  /casper/initrd
+  set background_color=black
+  set gfxpayload=keep # Maintain the graphical resolution through the booting
+  linux   /casper/vmlinuz autoinstall vga=788 FRONTEND_BACKGROUND=dark --- # Added autoinstall to make it unattended
+  initrd  /casper/initrd
 }