fai/config/scripts/GRUB_EFI/10-setup: Add EFI boot manager wipe for the Dell Venue 8 Pro tablet series.

fai/config/scripts/GRUB_EFI/10-setup: Use backquotes, make Midnight Commanders shell syntax highlighter happier.

bin/debian-edu-faiinstall: Adjust defaults for NFSROOT and TFTPROOT according to debian-edu-fai.conf.

conf/debian-edu/fai/debian-edu-fai.TEMPLATE/nfsroot.conf.in: Adjust paths of TFTPROOT and NFSROOT. More properly use our own namespace.

Revert "fai/config/scripts/EDU/50-cups-browsing: Assure that CreateRemoteCUPSPrinterQueues is set to 'Yes'."

This reverts commit c07b8a4e.

fai/config/package_config/STANDARD: python{,-minimal} are virtual, let's use python3{,-minimal} instead.

bin/debian-edu-faiinstall: Obviously 'test -d' is true for symlinks that point to a directory. In that case, we need to be more precise.

fai/config/files/etc/security/group.conf/: Use same group.conf for the WORKSTATION and ROAMING_WORKSTATION class. Duplicate that file.

bin/debian-edu-faiinstall: Create .ipxe file as ltsp.ipxe first, then create a symlink 'debian-edu-fai.ipxe' to reflect that this is not LTSP but FAI.

bin/debian-edu-faiinstall: Adjust installation of TFTP configuration files. Place files into /srv/tftp/ltsp to match Debian Edu 11 LDAP/DHCP settings.