Fixes #33033 - shell_escape template macro

New template macro `shell_escape` using
Ruby's `Shellwords.shellescape` for safe shell strings.

Use `shell_escape` for user input variables
in registration templates (`global` & `host_init`)

Fixes #33090 - load AIX OS attributes

Fixes #32540 - host_param_(true|false)? cleanup

let the `default_value` denote what we "read" by default from the host
(in the case the host doesn't have the param) and then compare it with
`true`/`false` (depending on the func) as done with the existing...

Fixes #31235 - drop Puppetclass models

Drops Puppetclass models and their usage.
Extracted in https://github.com/theforeman/foreman_puppet_enc/pull/81
Tests extracted in:
- hostgroup - https://github.com/theforeman/foreman_puppet_enc/pull/85

Fixes #32918 - Host registration - Update packages

New parameter `update_packages` for update of
all packages on the host when registered

Fixes #28221 - Adding passing of template scope for snippet rendering

In current implementation templates can be much complex by snippet.
Reusable pieces of template code that should be in the same scope like
their templates but they are not. This PR tries to solve that.

Fixes #27604 - added Fedora|Redhat CoreOS and IM

Fixes #31407 - prevent spaces for snapshot test files

Fixes #31370 - multi-host stub template snapshots (#8149)

Our snapshot template render test and generator only supports one host stub (ipv4 single NIC redhat OS). In order to test more ERB codepaths, we need a way to create snapshots against multiple host stubs (e.g. IPv6, dualstack, static IPv4 or IPv6, debian family). In order to do that, template metadata can be extended to define list of host stubs to create and test snapshots against....

Fixes #32394 - Use grub_pass macro instead of variable

The default Kickstart template uses obsolete @grub_pass variable
which are not being set anywhere. Maybe it's due to typo or else.
I suggest to use macro instead so it's possible to set the password
via host params and do not clone the template for this purpose only.