appimage: Build AppImage based on AlmaLinux 8.10
This follows the switch from SLES 15 based AppImages to AlmaLinux 8
based AppImages made by KDE. With SLES 15 there were problems with
building Qt 6.10 because of missing xcb-utils headers.
Don't build jpeg, pcre2, and zstd anymore but use the packages provided
by AlmaLinux 8.10.
- GnuPG-bug-id: T7509