AI-5965 - Multiple updates including puppet7 and c8 images

Number of commits:

• Add puppet7 and facter4 test, criticality depends on existing puppet_latest_allow_failure setting.
• Opt in management of code/.rubocop.yml , code/.rspec , code/.rspec_parallel and code/spec/spec_helper.rb
• Rubocop fix to code/spec/spec_helper.rb
• Update rubocop boilerplate to rubocop configuration dynamically from voxpupuli-gem
• CI images and examples to c8 and aiadm8.cern.ch
• addition of rubygem-i18n
• puppet6_latest test is now considered critical in all cases.

Fixes AI-5965