Add new rule service_dhcpd6_disabled

[mpurg]

Description:

• Add new rule service_dhcpd6_disabled based on service_dhcpd_disabled
• Update control 2.1.5 in ubuntu2404 CIS profile (Ensure dhcp server services are not in use)
• Define variable overrides for pkgname and servicename on ubuntu2404

[openshift-ci[bot]]

Hi @mpurg. Thanks for your PR.

I'm waiting for a ComplianceAsCode member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[github-actions[bot]]

Start a new ephemeral environment with changes proposed in this pull request:

rhel8 (from CTF) Environment (using Fedora as testing environment)

Fedora Testing Environment

Oracle Linux 8 Environment

[github-actions[bot]]

This datastream diff is auto generated by the check Compare DS/Generate Diff

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```diff New content has different text for rule 'xccdf_org.ssgproject.content_rule_service_dhcpd_disabled'. --- xccdf_org.ssgproject.content_rule_service_dhcpd_disabled +++ xccdf_org.ssgproject.content_rule_service_dhcpd_disabled @@ -5,6 +5,7 @@ [description]: The dhcpd service should be disabled on any system that does not need to act as a DHCP server. + The dhcpd service can be disabled with the following command: $ sudo systemctl mask --now dhcpd.service ```