Improve defining mutations

[AdvancedCodingMonkey]

• I currently manually curate defining mutations for new variants I add, there's no other resources that lists these that I know of. These files are found here (only on Github)
• I'll continue to manually curate for variants I track as this ensure the 'big ones' are absolutely 100% correct, but this information would be cool to a) display better & b) automatically generate for all variants (again, not available anywhere that I know of, but incredibly useful)
• Ideally we'd have auto-generated ones for all variants & this would be "overwritten" by a manual file if available (the manual file would display instead if detected)
• Some starting work on this was feat: add defining mutations #380, with a very ugly preview of the idea here -- ideas to make this prettier welcome!
• Cornelius would help us with writing the script to generate the files (he would probably generate them somewhere as part of his other workflows and we would pull them in)