Link to similar calculators

[blanchardjeremy]

I have started gathering similar tools here

https://docs.google.com/document/d/1b-QHxzKtoYfR4jQcsY8gH9xiVHUOEgSQknpdunFErFY/edit

Can someone open a pull request that includes these in the white paper (linked below the exisiting ones)?

For each one, we'd want to write a sentence or two about what we like about each one.

[richterdavid]

One more for you: https://safercovid.org/myrisk