Configuration of sshd moves from one config file to a config directory.
Therefore, checks should consider all those files, and the remediation should aim
to deliver fixes to one of those files in the config directory.

Tests that interact with this behavior have been added and are applicable for Fedora and RHEL9 products.

It now escapes the text contents if parts of them could be incorrectly interpreted as regexes.

The rule makes sure that the sshd configuration is distributed in the
/etc/ssh/sshd_config.d/ directory, and therefore it makes sense to scan that directory
in another rules.

Support in older jinja2 packages is not in a good shape.

Don't remediate when the config file already contains the include
directive.