mkarchiso: implement "file system transposition" support for UEFI

• mkarchiso: write a .uuid file to /.disk/ on ISO 9660 to allow GRUB to search for it

  Create a /.disk/INSERT_UUID_HERE.uuid file to implement something called "file system transposition". See https://www.mail-archive.com/grub-devel@gnu.org/msg34346.html for the proposal of it for grub-mkrescue.

  This will allow GRUB to search for the volume containing the file instead of hardcoding the ISO volume label or another file system or partition attribute in GRUB configuration. By only relying on the directory structure simplifies supporting medium preparation methods with manual partitioning such as https://wiki.archlinux.org/title/USB_flash_installation_medium#In_GNU/Linux_4

• configs/*/grub/grub.cfg: search for a .uuid file in /.disk/ and use the volume it's on

  Search for /.disk/%UUID_SEARCH_FILENAME%.uuid and pass the UUID of the volume it's on as archisodevice. mkarchiso will replace %UUID_SEARCH_FILENAME% with a hardcoded value generated using SOURCE_DATE_EPOCH durring ISO build.

  This allows to prepare an UEFI bootable installation medium by simply copying the directory structure without having to touch grub.cfg.

  Relying on the volume UUID instead of its LABEL also avoids collisions of multiple ISOs created in the same month.

  Fixes #202 (closed)

• Preload GRUB's NTFS, exFAT and UDF modules

  There are claims that some UEFI allegedly natively support NTFS. Preload the required GRUB modules to support booting from NTFS on such systems.

  Additionally preload the exFAT and UEF modules, because, why not?

archiso/mkarchiso

@@ -569,7 +569,13 @@ _make_common_bootmode_grub_copy_to_isofs() {
 
 # Prepare GRUB configuration files
 _make_common_bootmode_grub_cfg(){
-    local _cfg
+    local _cfg uuid_search_filename
+
+    # Create a .uuid file and place it in /.disk/ on ISO 9660 to provide a way for GRUB to search for the volume
+    uuid_search_filename="$(uuidgen --sha1 --namespace 93a870ff-8565-4cf3-a67b-f47299271a96 \
+        --name "${SOURCE_DATE_EPOCH} disk search UUID")"
+    install -d -m 0755 -- "${isofs_dir}/.disk"
+    : > "${isofs_dir}/.disk/${uuid_search_filename}.uuid"
 
     install -d -- "${work_dir}/grub"
 
@@ -577,7 +583,8 @@ _make_common_bootmode_grub_cfg(){
     for _cfg in "${profile}/grub/"*'.cfg'; do
         sed "s|%ARCHISO_LABEL%|${iso_label}|g;
              s|%INSTALL_DIR%|${install_dir}|g;
-             s|%ARCH%|${arch}|g" \
+             s|%ARCH%|${arch}|g;
+             s|%UUID_SEARCH_FILENAME%|${uuid_search_filename}|g" \
              "${_cfg}" > "${work_dir}/grub/${_cfg##*/}"
     done
     # Add all GRUB files to the list of files used to calculate the required FAT image size.
@@ -605,11 +612,11 @@ _make_bootmode_uefi-ia32.grub.esp() {
 
     # Create EFI binary
     # Module list from https://bugs.archlinux.org/task/71382#comment202911
-    grubmodules=(all_video at_keyboard boot btrfs cat chain configfile echo efifwsetup efinet ext2 f2fs fat font \
+    grubmodules=(all_video at_keyboard boot btrfs cat chain configfile echo efifwsetup efinet exfat ext2 f2fs fat font \
                  gfxmenu gfxterm gzio halt hfsplus iso9660 jpeg keylayouts linux loadenv loopback lsefi lsefimmap \
-                 minicmd normal part_apple part_gpt part_msdos png read reboot regexp search search_fs_file \
-                 search_fs_uuid search_label serial sleep tpm usb usbserial_common usbserial_ftdi usbserial_pl2303 \
-                 usbserial_usbdebug video xfs zstd)
+                 minicmd normal ntfs ntfscomp part_apple part_gpt part_msdos png read reboot regexp search \
+                 search_fs_file search_fs_uuid search_label serial sleep tpm udf usb usbserial_common usbserial_ftdi \
+                 usbserial_pl2303 usbserial_usbdebug video xfs zstd)
     grub-mkstandalone -O i386-efi \
                       --modules="${grubmodules[*]}" \
                       --locales="en@quot" \
@@ -682,11 +689,11 @@ _make_bootmode_uefi-x64.grub.esp() {
 
     # Create EFI binary
     # Module list from https://bugs.archlinux.org/task/71382#comment202911
-    grubmodules=(all_video at_keyboard boot btrfs cat chain configfile echo efifwsetup efinet ext2 f2fs fat font \
+    grubmodules=(all_video at_keyboard boot btrfs cat chain configfile echo efifwsetup efinet exfat ext2 f2fs fat font \
                  gfxmenu gfxterm gzio halt hfsplus iso9660 jpeg keylayouts linux loadenv loopback lsefi lsefimmap \
-                 minicmd normal part_apple part_gpt part_msdos png read reboot regexp search search_fs_file \
-                 search_fs_uuid search_label serial sleep tpm usb usbserial_common usbserial_ftdi usbserial_pl2303 \
-                 usbserial_usbdebug video xfs zstd)
+                 minicmd normal ntfs ntfscomp part_apple part_gpt part_msdos png read reboot regexp search \
+                 search_fs_file search_fs_uuid search_label serial sleep tpm udf usb usbserial_common usbserial_ftdi \
+                 usbserial_pl2303 usbserial_usbdebug video xfs zstd)
     grub-mkstandalone -O x86_64-efi \
                       --modules="${grubmodules[*]}" \
                       --locales="en@quot" \