Establish Methodology for Criticality of Issues

[jakehildreth]

We need a methodology for ranking risk. This should be in place before we surface risk ratings to the user.

[jakehildreth]

PR #121 submitted in support of this effort. Once the flowcharts are solid, we can convert them to maths and stuff.

[jakehildreth]

I have an Excel spreadsheet that I need to convert to Markdown table and Mermaid chart. Once that's uploaded, I will close this issue.