Refactor ISOs and adjacent bug-fixes

[tenthirtyam]

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Summary of Pull Request

Refactors ISO configurations

Type of Pull Request

• This is a bug fix.
• This is an enhancement or feature.
• This is a code style / formatting update.
• This is a documentation update.
• This is a refactoring update.
• This is something else.
  Please describe:

Context of the Pull Request

• Uses vendor / distributor .iso file name and checksum mentioned in disscusion ISO filename, checksum and hash method #72
• Adds/updates build variables to include iso_path, iso_file, iso_checksum_type, and iso_checksum_value mentioned in disscusion ISO filename, checksum and hash method #72
• Updates code style for the variables passed to a templatefile

Also in the payload:

• Replaces the term "redhat-variant" with "redhat-derivative"
• Adds ansible to Ubuntu 20.04 and 18.06 [ENHANCEMENT] Use ansible provisioner for Linux configuration and packages #54
• Addresses some issues mentioned seen in Building vs. Using #80
• Updates documentation

Related to Existing Issues

Issue Number: See Context of the Pull Request

Test and Documentation Coverage

• Tests have been completed (for bug fixes / features).
• Documentation has been added / updated (for bug fixes / features).

Breaking Changes?

• Yes, there are breaking changes.
• No, there are no breaking changes.

[tenthirtyam]

✅ Self Reviewed
✅ Self Approved

[github-actions]

I'm going to lock this pull request because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues. If you have found a problem that seems related to this change, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.