Add syslog_files rules test scenarios

[iokomin]

Description:

In order to get #4379 verified introduced test scenarios for rsyslog_files_* rules.
Test scenarios check include log rules, include() object (rsyslog v8.33.0+: RHEL8, OL8, Fedora) and $IncludeConfig directive.

Added tests for rules:

• rsyslog_files_groupownership
• rsyslog_files_ownership
• rsyslog_files_permissions

Testing:

• Checked ol, rhel, and fedora builds to pass
• Using OL7.6 VM libvirt backend checked scenarios to pass
• Verified corresponding DEBUG "*-initial.verbose.log" logs for OVAL definitions to filter and check expected test configs and log files.

[mildas]

The preparation part (create test files, test config and directory) is still same for each test scenario, the only difference is number of files.
Could you create function for it (e.g. with number of files as parameter)? This function could be placed in group_ensure_rsyslog_log_file_configuration folder and used by all test scenarios you made. And test scenarios would only call it and then contain the important part - setting ownership/permissions and creating rsyslog config.

[iokomin]

@mildas thanks for your review, suggested changes make sense to me.
Please find updated version of PR, it should address all requested changes.

[mildas]

Thank you for update. I have just few more minor issues, mostly with so much empty lines, so please remove some of them (e.g. between chgrp, chmod etc.)

[mildas]

Tried these test on top of #4379 fix (on rhel8 and fedora30) and they pass/fail as expected. Thank you!