Fixes #37011 - Apply latest Ubuntu Autoinstall userdata changes

• Add explicit fallback for offline installation
• Replace deprecated lock-passwd with lock_passwd
• Remove empty ssh keys array if none provided

Fixes #35840 - Install chrony on RHEL 7

Fixes #35397 - Preseed Autoinstall incorporate host_params

• Param 'keyboard' to set default layout
• Param 'lang' to set default locale
• Adapt template snapshot accordingly

Co-authored-by: Bastian Schmidt <schmidt@atix.de>
Co-authored-by: Evgeni Golov <evgeni@golov.de>

Refs #35530 - Alternative approach to save_to_file

save_to_macro generates a command using cat and a heredoc string.
However, if the content to be written contains a heredoc using the same
delimiter, save_to_macro's heredoc will be terminated by it, leading to...

Fixes #35530 - Make save_to_file macro safer (#9426)

• Fixes #35530 - Make save_to_file macro safer

save_to_file does

cat <<EOF >$file
$content
EOF

but if `$content` contains a heredoc terminated with `EOF`, it
terminates the heredoc that save_to_file creates....

Fixes #35137 - Permit setting puppet tag during install

Fixes #34700 - autoinstall template enable root user

The `identity` field doesn't allow to add/edit root as a user.
Therefore, the user-data field must be used. Compare the Ubuntu
Autoinstall documentation:
https://ubuntu.com/server/docs/install/autoinstall-reference#identity...

Fixes #34339 - sanitize fqdn in tests

Tests were almost not using the fqdn defined in settings.yaml.test
That is quite confusing at first sight and we should not override this value by fixtures, only if overriden in the same test file.

Fixes #32632 - initial verison of Ubuntu autoinstall templates

Signed-off-by: Lukas Zapletal <lzap+git@redhat.com>

Fixes #34214 - use host_param_true? to detect puppet6-repo