Removing custom UEFI shell boot loader configs
configs/releng/build.sh: Copying the edk2-shell based Shell_Full.efi to the root of the iso/ efi image as 'shellx64.efi' is automatically picked up by certain hardware and by systemd-boot. This makes all custom UEFI shell configuration obsolete.
configs/releng/efiboot/loader/entries/uefi-shell-*.conf: Removing obsolete custom UEFI shell boot loader configuration.
Closes #14 (closed)