Add Joliet file system to the ISO

Joliet ensures correct file names capitalization on operating systems that support Joliet but not support Rock Ridge.
Implements https://gitlab.archlinux.org/archlinux/archiso/-/issues/45 .

archiso/mkarchiso

@@ -560,6 +560,8 @@ _make_iso() {
     xorriso -as mkisofs \
             -iso-level 3 \
             -full-iso9660-filenames \
+            -joliet \
+            -joliet-long \
             -rational-rock \
             -volid "${iso_label}" \
             -appid "${iso_application}" \