Description

• Converted major from type String to type List of String.
• Converted ascii validation to String validation.

Closes #268
Closes #354
Closes #226

Before, or right after merging into master, we will need to update the DB so that the hacker documents are of the correct type.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules